Utilisateur:Wart Dark/Guerre de tranchée
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La guerre de tranchée est une forme de guerre dans laquelle deux armées s'affrontent sur des lignes statiques de fortifications enterrées, face à face. La guerre de tranchée est apparue pour la première fois au cours de la Guerre de Crimée (1853-1856), a refait surface avec la Guerre de Sécession américaine (1861-1965) et la Guerre russo-japonaise de 1904-1905, pour atteindre son apogée de violence et de carnage sur le front ouest de la Première Guerre mondiale (1914-1918) . Son existence s'explique par la considérable amélioration des armes à feu et de l'artillerie de cette époque, qui n'a pas eu d'équivalence sur le plan de la mobilité des troupes et des communications. L'apparation des blindés, à la fin de la première guerre mondiale, et les progrès en logistique et télécommunications depuis ce conflit, l'ont rendu obsolète, à quelques exceptions près.
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[modifier] Contexte
Les fortifications sont aussi anciennes que la guerre elle-même, cependant, du fait de la relative petite taille des armées et et de la faible variété des armes, il n'était traditionnellement pas possible de défendre plus qu'une ligne défensive courte ou un seule place forte. Les grandes fortifications de l'Antiquité, telles la grande muraille de Chine ou le Mur d'Hadrien, sont les rares exceptions à cette règle générale, et n'étaient pas d'ailleurs conçus pour être impénétrables, mais faisaient plutôt office de contrôles des frontières, empêchant ainsi de légères pénétrations sur le territoire, dues aux pillards et bandits, et des flux migratoires non désirés.
Bien que l'armement et la la fortification aient fortement progressé à partir du XVIe siècle, avec l'arrivée du mousquet et de l'artillerie à poudre, la règle traditionnelle selon laquelle une fortification exige un grand corps de troupes pour être défendue était encore vraie. Un nombre restreint de troupes ne pouvait pas maintenir un volume de feu suffisant pour repousser une attaque déterminée.
[modifier] Guerre de siège
La plupart des techniques utilisées dans la guerre de tranchée était déjà employées durant les sièges. Étudier ceux-ci permet ainsi de mieux aborder la guerre de tranchée.
Jules César dans son De Bello Gallico décrit comment au Siège d'Alésia les légions romaines créèrent deux énormes murs de fortification autour de la cité : une ligne de travaux défensifs (fossé suivi d'une palissade de pieux agrémenté de tours) de plus de 16 km, la contrevallation, édifiée pour empêcher les sorties des assiégés, et une deuxième ligne de défense similaire de 21 km, la circonvallation, tournée vers l'extérieur et destinée à protéger les assaillants d'une éventuelle armée de secours.
Confronté à la famine, les gaulois se sont par la suite rendus, sans avoir tous combattus. Thucydide décrit le similaire, mais raté, siège de Syracuse par les athéniens durant la guerre du Péloponnèse.
Une fois les engins de siège développés les techniques d'assaut furent immuables. L'armée attaquante entourait la ville, puis celle-ci était invitée à se rendre. S'ils refusaient, les assaillants entouraient la cité de fortifications temporaires pour stopper les sorties de troupes depuis la forteresse ou 
relief getting in ⇔ ???. Puis, ils établissaient une longueur de fossés parallèles aux défenses, mais hors de portée de leur artillerie, et creusaient des fossés en zigzag vers la ville, de sorte qu'il ne puisse être pris en enfilade. Une fois à portée d'artillerie un autre fossé parallèle, avec des caches d'armes, était creusé. Au besoin, on utilisait les premiers tirs d'artillerie pour couvrir les travaux de constructions. Ce processus était répété jusqu'à ce que des pièces d'artillerie soit assez proches pour faire une brèche dans la ligne ennemie. Pour que " en:Forlorn Hope ⇔ ???" et leurs troupes de soutien deviennent assez proches pour exploiter la brèche, plus de tranchées en zigzag peuvent être creusées plus près des murs avec des fossés plus parallèles pour protéger et cacher les troupes attaquantes. Après chaque avancée, les assiégeants demandait la reddition. Celle-ci reposait sur une menace implicite : si la vague d'assaut suivante franchissait les défenses adverses avec succès, les assiégés ne devaient s'attendre à aucune pitié.
[modifier] Pa Maori
Les Maoris de Nouvelle Zélande avaient construit des palissades appelées Pa sur des collines et de petites péninsules pendant les siècles précédents leur contact avec les européens. Celles-ci ressemblaient aux petites collines fortifiées de l'âge de fer qui ponctuent les paysages britanniques et irlandais. Quand les Maoris rencontrèrent les forces coloniales anglaises, envoyées en 1840 pour annexer l'ile, ils firent évolué leurs Pas en un système défensif très efficace de fossés, équipant de fusils (rifle) les puits et les pirogues, ce qui antidate les systèmes similaires développés en Amérique et en Europe. Durant la le Pa modernisé a effectivement contre-balancé la disparité accablante en nombre et en armement. A la bataille de Ohaeawai en 1845, à Rangiriri en 1864, et à Gate Pa la même année, les forces coloniales britanniques découvrirent que les attaques frontales sur une Pa étaient inefficaces et extrêmement coûteuses en hommes.
[modifier] Développement
Le premier tournant dans le développement de la guerre de tranchée fut l'enrôlement de grande armées par conscription, apparue en l'an II du calendrier républicain français puis au cours des guerres napoléoniennes. Avant cette époque, les armées se sont toujours composées d'un nombre restreint de soldats qui ne pouvaient pas défendre longtemps un grand territoire. Les batailles étaient brèves ou dégénérées en sièges.
Les premières lignes militaires fortifiées furent les lignes de Torres Vedras, qui s'étendirent sur de nombreux kilomètres, construites par le Portugal en 1810, pendant la campagne d'Espagne, sous la direction du génie militaire de l'armée britannique.
L'avantage des grandes armées, outre évidemment le nombre de soldats, est qu'elles sont beaucoup plus difficilement débordables, mais il était encore possible avec des charges de cavalerie et d'infanterie qu'une armée traverse une autre par un assaut direct. Cette tactique est devenue de plus en plus suicidaire avec l'amélioration des armes à feu au milieu du XIXe siècle.
Ainsi, quand la guerre civile américaine débuta en 1861, on combattait avec la tactique de l'ère napoléonnienne et des siècles précèdents. Avant sa fin sanglante en 1865, la guerre avait pris une tournure semblable à celle de la future Première Guerre mondiale, avec des tranchées armées de mitrailleuses Gatling, des champs fortifiés, et une forte mortalité. Le Siège de Petersburg proche de la fin de la guerre, avec ses tranchées et formations statiques, diffère radicalement des batailles précédentes telles que la première bataille de Bull Run où les manœuvres étaient encore possibles, et fut ainsi dans le prolongement de la Bataille de Gettysburg, où la fameuse charge de Pickett révéla la futilité d'un assaut direct sur une ligne opposée.
Deux principaux facteurs sont responsables de ce changement. Le premier est la généralisation des fusils (tel le .58 Springfield), assemblés par milliers. Efficaces à une portée double de celle des smoothbore ⇔ ??? des guerres napoléoniennes, c'est à dire capables d'abattre un homme à plus de 1000 mètres, ils permirent à des hommes s'abritant dans un fossé ou derrière un obstacle improvisé de tenir à distance des attaquants bien plus éloignés qu'auparavant ; ceux-ci ne pouvaient pas traverser la zone les séparant de leur adversaire assez rapidement pour éviter la mort. Cela pousse chaque camp à limiter ses attaques et à camper sur ces positions indéfiniment.
Cette impuissance dramatique fut aggravée par la persistance d'une tactique colomnaire, pourtant dépassé, qui n' a fait qu'amplifier des pertes, c'est là le second facteur ; c'est seulement vers la fin de la guerre que les tactiques d'escarmouches devinrent standards. Ainsi la première réponse à la puissance de feu accrue fut la couverture, et une seconde, la dispersion était éventuellement adoptée. L'armure n'était plus une option envisageable, comme elle le fut au temps des arcs et des arbalètes, et une vitesse supérieure n'était guère plus possible. Il faudra attendre d'importants progrès technologiques pour que ces deux solutions alternatives se concrétisent avec les blindés.
Après la fin de la guerre civile américaine d'autres facteurs aggravèrent le déséquilibre entre stratégie offensive et stratégie défensive. La principale fut l'usage du fil de fer barbelé, inventé en 1874, qui ralentit considérablement la progression des assaillants, notamment s'il est disposé sur plusieurs lignes situées tout le long des tranchées des deux camps, et les expose ainsi au feu ennemi sur une durée infligeant des pertes inacceptables. Le barbelé peut en plus être rendu blessant et plus difficile à franchir, s'il est un peu détendu.
L'artillerie fait partie de la guerre depuis l'époque classique, mais de l'essor de la poudre jusqu'à la guerre de tranchée elle avait été la force principale de massacre ; avec les premières de ces guerres de tranchée elle fut supplantée temporairement par les mitraillettes. C'est l'invention de breechloading guns ⇔ ??? en acier par Krupp qui restaura sa suprématie, comme le prouva la guerre franco-prusse de 1870. Enfin l'introduction d'obus hautement explosifs, amplifia par seize sa capacité à tuer. A cela s'ajoute les mécanismes hydrauliques de recul, utilissé d'abord par les français avec le canon de 75 modèle 1897, le fameux « French 75 », ayant significativement augmenté la cadence de tir. Ceux-ci ont semé la terreur, amenant l'efficacité de l'artillerie a des degrés auparavant inimaginables, au point que la zone séparant les deux armées soit devenu, un « no man's land », une bande sans soldats vivants dont la traversée était fatale. A l'aube du XXe siècle, l'offensive ne pouvait plus aboutir ; la guerre de tranchée serait dorénavant une guerre d'usure.
[modifier] Application
Bien que les nouvelles armes à feure et la Conscription changèrent dramatiquement la nature de la guerre, la plupart des armées ignorèrent complètement les implications stratégiques de ces changements et n'y furent donc pas préprarée. Ainsi, au début de la première guerre mondiale, les forces allemandes comme alliées (notamment françaises et britanniques) avaient planifié une guerre courte à la stratégie et aux tactiques qui se pratiquaient depuis Napoléon.
Cependant, lorsque la guerre fut déclarée, les états-majors de ces forces ont rapidement compris qu'avec les armes modernes même un trou peu profond dans le sol pourrait être défendu par une poignée d'infanterie. Attaquer de front revenait à aller au devant de pertes considérables, les débordements des flancs étaient donc essentiels. Après la Bataille de l'Aisne, en septembre 1914, une série prolongée de débordement de flancs fut essayés, sans succès. Prolongeant ainsi les lignes défensives, dans la célèbre « course à la mer », les armées allemandes et françaises creusèrent finalement une longue et unique paire de tranchés sur tout le front, c'est à dire de la frontière suisse au Sud jusqu'à la côte belge de la Mer du Nord.
La guerre de tranchée a dominé le conflit sur le front ouest du 16 septembre 1914, jusqu'à l'offensive allemande de la seconde bataille de la Marne, « l'opération Michael », lancée le 21 mars, 1918. Les petits fossés improvisés des premiers mois se sont rapidement développés plus profonds et et plus complexes, devenant graduellement de vastes zones pour la sécurisation des travaux défensifs.
L'espace entre les deux tranchées opposées fut appelés "no man's land", sa taille dépendait du champ de bataille. Sur le Front occidental, il était typiquement compris entre 100 et 300 yards (convertir !), mais atteignait seulement 30 yards à la Bataille de Vimy. Après le retrait allemand sur la Ligne Siegfried en mars 1917, il s'est étendu au-delà d'un kilomètre sur cette partie du front. A l'opposé au "Quinn's Post" dans les confins du champ de bataille d'Anzac aux Dardanelles, les lignes étaient distantes de seulement 15 mètres et les lancées de grenade, d'une tranchée à l'autre, étaient permanent.
Sur le front Est, la zone à couvrir était si vaste et la distance entre les usines fournissant les obus, les balles, les fils barbelés était si grande, que aucune guerre de tranchée comparable à celle du front Ouest n'eut lieu.
Dans les Alpes, la guerre de tranchée s'est déployée dans les trois dimensions spatiales : les pentes raides et dangereuses rendaient difficiles d'accès des positions qui culminaient jusqu'à une altitude de 3900 mètres (l'Ortles fut une position d'artillerie proche du front). La gestion des tranchées et leur profil fut adaptés au terrain escarpé et rude ainsi qu'aux dures conditions météorologiques. De nombreuses tranchées furent ainsi construites dans des glaciers comme ceux de l'Adamello-Presanella ou du Marmolada dans le massif des Dolomites.
[modifier] Système défensif
Very early in the war the British defensive doctrine suggested a main trench system of three parallel lines with each line connected by communications trenches. The point at which a communications trench intersected the front trench was of critical importance and was usually heavily fortified. The front trench was lightly garrisoned and typically only occupied in force during "stand to" at dawn and dusk. Between 70 and 100 yards behind the front trench was located the support (or "travel") trench to which the garrison would retreat when the front trench was bombarded. Between 300 and 500 yards further to the rear was located the third reserve trench, where the reserve troops could amass for a counter-attack if the front trenches were captured. This defensive layout was soon rendered obsolete as the power of the artillery grew; however, in certain sectors of the front, the support trench was maintained as a decoy to attract the enemy bombardment away from the front and reserve lines. Fires were lit in the support line to make it appear inhabited, and any damage due to shellfire was immediately repaired.
Temporary trenches were also built. When a major attack was planned, assembly trenches would be dug near the front trench. These were used to provide a sheltered place for the waves of attacking troops who would follow the first waves leaving from the front trench. "Saps" were temporary, unmanned, often dead-end utility trenches dug out into no man's land. They fulfilled a variety of purposes such as connecting the front trench to a listening post close to the enemy wire or providing an advanced "jumping-off" line for a surprise attack.
When one side's front line bulged towards the opposition, a "salient" was formed. The concave trench line facing the salient was called a "re-entrant". Large salients were perilous for their occupants because they could be assailed from three sides.
Behind the front system of trenches there were usually at least two more partially prepared trench systems, kilometres to the rear, ready to be occupied in the event of a retreat. The Germans often prepared multiple redundant trench systems; in 1916 their Somme front featured two complete trench systems, one kilometre apart, with a third partially complete system a further kilometre behind. This duplication made a decisive breakthrough virtually impossible. In the event that a section of the first trench system was captured, a "switch" trench would be dug to connect the second trench system to the still-held section of the first.
The Germans made something of a science out of designing and constructing defensive works. They used reinforced concrete to construct deep, shell-proof, ventilated dugouts as well as strategic strongpoints. They were more willing than their opponents to make a strategic withdrawal to a superior prepared defensive position. They were also the first to apply the concept "defence in depth", where the front-line zone was hundreds of yards deep and contained a series of redoubts rather than a continuous trench. Each redoubt could provide supporting fire to its neighbours, and while the attackers had freedom of movement between the redoubts, they would be subjected to withering enfilade fire. The British eventually adopted a similar approach, but it was incompletely implemented when the Germans launched the 1918 "Spring Offensive" and proved disastrously ineffective.
[modifier] Construction
Trenches were never straight but were dug in a square-toothed pattern that broke the line into bays connected by traverses. This meant that a soldier could never see more than 10 metres or so along the trench. Consequently, the entire trench could not be enfiladed if the enemy gained access at one point or if a bomb or shell landed in the trench; the fragmentation (often incorrectly called shrapnel) could not travel far. The side of the trench facing the enemy was called the parapet and had a fire step. The rear of the trench was called the parados. The parados protected the soldier's back from fragmentation from shells falling behind the trench. If the enemy captured the trench, then the parados would become their "parapet". The sides of the trench were revetted with sandbags, wooden frames and wire mesh. The floor of the trench was usually covered by wooden duckboards.
Dugouts of varying degrees of luxury would be built in the rear of the support trench. British dugouts were usually 8 to 16 feet deep, whereas German dugouts were typically much deeper, usually a minimum of 12 feet deep and sometimes dug 3 stories down with concrete staircases to reach the upper levels.
To allow a soldier to see out of the trench without exposing his head, a loophole would be built into the parapet. A loophole might simply be a gap in the sandbags or it might be fitted with a steel plate. German snipers used armour-piercing bullets that allowed them to penetrate loopholes. The other means to see over the parapet was the trench periscope—in its simplest form, just a stick with two angled pieces of mirror at the top and bottom. In the Anzac trenches at Gallipoli where the Turks held the high ground, the periscope rifle was developed to enable the Australians and New Zealanders to snipe at the enemy without exposing themselves over the parapet.
There were three standard ways to dig a trench: entrenching, sapping and tunnelling. Entrenching, where a man would stand on the surface and dig downwards, was most efficient as it allowed a digging party to dig the length of the trench simultaneously. However, entrenching left the diggers exposed above ground and hence could only be carried out when free of observation, such as in a rear area or at night. Sapping involved extending the trench by digging away at the end face. The diggers were not exposed, but only one or two men could work on the trench at a time. Tunnelling was like sapping except that a "roof" of soil was left in place while the trench line was established and then removed when the trench was ready to be occupied. The guidelines for British trench construction stated that it would take 450 men 6 hours (at night) to complete 250 metres of a front-line trench system. Thereafter the trench would require constant maintenance to prevent deterioration caused by weather or shelling.
The battlefield of Flanders, which saw some of the worst fighting, presented numerous problems for the practice of trench warfare, especially for the British, who were often compelled to occupy the low ground. In most places, the water table was only a metre or so below the surface, meaning that any trench dug in the ground would quickly flood. Consequently, many "trenches" in Flanders were actually above ground and constructed from massive breastworks of sandbags (actually filled with clay). Initially, both the parapet and parados of the trench were built in this way, but a later technique was to dispense with the parados for much of the trench line, thus exposing the rear of the trench to fire from the reserve line in case the front was breached.
[modifier] Géographie
The confined, static and subterranean nature of trench warfare resulted in it developing its own peculiar form of geography. In the forward zone, the conventional transport infrastructure of roads and rail were replaced by the network of trenches and light tramways. The critical advantage that could be gained by holding the high ground meant that minor hills and ridges gained enormous significance. Many slight hills and valleys were so subtle as to have been nameless until the front line encroached upon them. Some hills were named for their height in metres, such as Hill 60. A farmhouse, windmill, quarry or copse of trees would become the focus of a determined struggle simply because it was the largest identifiable feature. However, it would not take the artillery long to obliterate it, so that thereafter it became just a name on a map.
Battlefield features could be given a descriptive name ("Polygon Wood" near Ypres or "Lone Pine"), a whimsical name ("Sausage Valley" and "Mash Valley" on the Somme), a unit name ("Inniskilling Inch" at Helles named for the Royal Inniskilling Fusiliers) or the name of a soldier ("Monash Valley" at Anzac named after General John Monash). Prefixing a feature with "Dead Man's" was also popular for obvious reasons, such as "Dead Man's Road" leading in to Pozières, "Dead Man's Ridge" at Anzac or "Le Mort Homme" at Verdun. There were numerous trench networks named "The Chessboard" or "The Gridiron" because of the pattern they described. For the Australians at Mouquet Farm, the advances were so short and the terrain so featureless that they were reduced to naming their objectives as "points" on the map, such as "Point 81" and "Point 55".
Enemy trenches, which would become objectives in an attack, needed to be named as well. Many were named for some observed event such as "German Officers' Trench" at Anzac (where a couple of German officers were sighted) or "Ration Trench" on the Somme (where German ration-carrying parties were sighted). The British gave an alcoholic flavour to the German trenches in front of Ginchy: "Beer Trench", "Bitter Trench", "Hop Trench", "Ale Alley" and "Pilsen Trench". Other objectives were named according to their role in the trench system such as the "Switch Trench" and "Intermediate Trench" on the Somme.
Some sections of the British trench system read like a Monopoly board, with names such as "Park Lane" and "Bond Street". British regular divisions habitually named their trenches after units, which resulted in names such as "Munster Alley" (Royal Munster Fusiliers), "Black Watch Alley" (Black Watch Regiment) and "Border Barricade" (Border Regiment). The Anzacs tended to name features after soldiers ("Plugge's Plateau", "Walker's Ridge", "Quinn's Post", "Johnston's Jolly", "Russell's Top", "Brind's Road" and so forth).
[modifier] La vie dans les tranchées
An individual soldier's time in the front-line trench was usually brief; from as little as one day to as much as two weeks at a time before being relieved. The Australian 31st Battalion once spent 53 days in the line at Villers Bretonneux, but such a duration was a rare exception. A typical British soldier's year could be divided as follows:
- 15% front line
- 10% support line
- 30% reserve line
- 20% rest
- 25% other (hospital, travelling, leave, training courses, etc.)
Even when in the front line, the typical soldier would only be called upon to engage in fighting a handful of times a year—making an attack, defending against an attack or participating in a raid. The frequency of combat would increase for the men of the "elite" fighting divisions—on the Allied side; the British regular divisions, the Canadian Corps, the French XX Corps and the Anzacs.
Some sectors of the front saw little activity throughout the war, making life in the trenches comparatively easy. When the I Anzac Corps first arrived in France in April 1916 after the evacuation of Gallipoli, they were sent to a relatively peaceful sector south of Armentières to "acclimatise". Other sectors were in a perpetual state of violent activity. On the Western Front, Ypres was invariably hellish, especially for the British in the exposed, overlooked salient. However, quiet sectors still amassed daily casualties through sniper fire, artillery and gas. In the first six months of 1916 before the launch of the Somme Offensive, the British did not engage in any significant battles on their sector of the Western Front and yet suffered 107,776 casualties.
A sector of the front would be allocated to an Corps d'armée, usually containing three divisions. Of these two would occupy adjacent sections of the front and the third would be in rest to the rear. This break down of duty would continue down through the army structure so that within each front-line division, typically containing three infantry brigades, two brigades would occupy the front and the third would be in reserve. Within each front-line brigade, typically containing four battalions (regiments for the Germans), two battalions would occupy the front with two in reserve. And so on for companies and platoons. The lower down the structure this division of duty proceeded, the more frequently the units would rotate from front-line duty to support or reserve.
During the day, snipers and artillery observers in balloons made movement perilous, so the trenches were mostly quiet. Consequently, the trenches were busiest at night when cover of darkness allowed the movement of troops and supplies, the maintenance and expansion of the barbed wire and trench system, and reconnaissance of the enemy's defences. Sentries in listening posts out in no man's land would try to detect enemy patrols and working parties or indications that an attack was being prepared.
Raids were carried out in order to capture prisoners and "booty"—letters and other documents that provide intelligence about the unit occupying the opposing trenches. As the war progressed, raiding became part of the general British policy, the intention being to maintain the fighting spirit of the troops and to deny no man's land from the Germans. Such dominance was achieved at a high cost, and a post-war British analysis concluded that the benefits were probably not worth the price.
Early in the war, surprise raids would be mounted, particularly by the Canadians, but increased vigilance made achieving surprise difficult as the war progressed. By 1916, raids were carefully planned exercises in combined arms and involved close co-operation of infantry and artillery. A raid would begin with an intense artillery bombardment designed to drive off or kill the front-trench garrison and cut the barbed wire. Then the bombardment would shift to form a "box", or cordon, around a section of the front line to prevent a counter-attack intercepting the raid.
[modifier] La mort dans les tranchées
The intensity of World War I trench warfare meant that about 10% of the fighting soldiers were killed. This compared to 5% killed during the Second Boer War and 4.5% killed during World War II. For British and Dominion troops serving on the Western Front, the proportion of killed was 12% while the total proportion of troops who became casualties (killed or wounded) was 56%. Considering that for every front-line infantryman there were about 3 soldiers in support (artillery, supply, medical, etc.), it was highly unlikely for a fighting soldier to survive the war without sustaining some form of injury. Indeed many soldiers were injured more than once during the course of their service.
Medical services were primitive and life-saving antibiotics were undiscovered. Relatively minor injuries could prove fatal through the onset of infection and gangrene. The Germans recorded that 12% of leg wounds and 23% of arm wounds resulted in death, mainly through infection. The Americans recorded that 44% of casualties that developed gangrene died. Half of those who were wounded in the head died and only 1% of those wounded in the abdomen survived.
Three-quarters of the wounds inflicted during the war came from shell fire. The wound resulting from a shell fragment was usually more traumatic than a gunshot wound. A shell fragment would often introduce debris making it more likely that the wound would become infected. These factors meant that a soldier was three times more likely to die from a shell wound to the chest than from a gunshot wound. The blast from shell explosions could also kill by concussion. In addition to the physical effects of shell fire there was the psychological damage. Men who had to endure a prolonged bombardment would often suffer debilitating shell shock, a condition that was not well understood at the time.
As in many other wars, World War I's greatest killer was disease. Sanitary conditions in the trenches were quite poor, and common infections included dysentery, typhus, and cholera. Many soldiers suffered from parasites and related infections. Poor hygiene also led to conditions such as trench mouth and trench foot. Another common killer was exposure, since the temperature within a trench in the winter could easily fall below zero degrees celsius. (32 F)
Burial of the dead was usually a luxury that neither side could easily afford. The bodies would lie in no man's land until the front line moved, by which time the bodies were often unidentifiable. On some battlefields, such as at the Nek in Gallipoli, the bodies were not buried until after the war. On the Western Front, bodies continue to be found as fields are ploughed and building foundations dug.
At various times during the war—particularly early on—official truces were organised so that the wounded could be recovered from no man's land and the dead could be buried. Generally though, the higher commands disapproved of any slackening of the offensive for humanitarian reasons and so ordered their troops not to permit enemy stretcher bearers to operate in no man's land. However, this order was almost invariably ignored by the soldiers in the trenches, who knew that it was to the mutual benefit of the fighting men of both sides to allow the wounded to be retrieved. So, as soon as hostilities ceased, parties of stretcher bearers, marked with Red Cross flags, would go out to recover the wounded, sometimes swapping enemy wounded for their own. There were occasions when this unofficial cease fire was exploited to conduct a reconnaissance or to reinforce or relieve a garrison. One famous truce was the Christmas truce between British and German soldiers in the winter of 1914 on the front near Armentieres. German soldiers began singing Christmas carols and soon soldiers left their trenches. The soldiers exchanged gifts and stories, and played several games of football. As mentioned previously, the commanders of the warring nations disapproved of this cease fire, and the British court-martialed several of their soldiers. The spirit of this truce is potrayed in the 2005 movie Merry Christmas (Joyeux Noël).
[modifier] Armement
[modifier] Équipement de l'infanterie
The common infantry soldier had four weapons to use in the trenches: the rifle, bayonet, shotgun and grenade.
The standard British rifle was the .303-in. (7.7 mm) Short Magazine Lee-Enfield (SMLE), originally developed as a cavalry carbine, with a maximum range (for sniping) of 1400yd (1280 m), though its effective range was more like 200yd (180 m). British infantry training emphasised rapid rifle fire rather than accuracy. Early in the war, the British were able to defeat German attacks at Mons and the First Battle of Ypres using massed rifle fire, but as trench warfare developed, opportunities to assemble a line of riflemen became rare. The German counterpart to the Lee-Enfield was the 8 mm (.312-in.) Mauser Gewehr 98 (G98), which was equal to or better than its British counterpart in accuracy, range, and reliability. However, it was less suited to rapid fire due to its 5-round magazine, half that of the British rifle. The French Lebel and Russian Mosin-Nagant rifles were generally inferior to the German and British weapons in most fields, especially reliability and workmanship.
The British soldier was equipped with a 21-in. (53cm) sword bayonet, which was too long and unwieldy to be particularly effective in close quarters combat. However, bayonet use was safer than firing the rifle which, in a mêlée, might strike an ally instead of an enemy. British figures recorded that only 0.3% of wounds were caused by bayonets; however, a strike from a bayonet was highly likely to result in death. A bayonet charge could be effective at inducing terror in an opponent, encouraging them to flee or surrender. The bayonet was used to finish off wounded enemy during an advance, saving ammunition while reducing the possibility of being attacked from the rear. Imperial German soldiers generally carried the M1898 "Butcher-blade" bayonet, which was a deadly effective weapon in the open, but like the British bayonet, difficult to use in the narrow trenches.
Many soldiers preferred a short-handled spade or entrenching tool over a bayonet. They would sharpen the blade to a knife edge so it was just as effective as a bayonet, and the shorter length made them handier to use in the confined quarters of the trenches. These tools could then be used to "dig in" after they had taken a trench.
Since the troops were often not adequately equipped for trench warfare, improvised weapons were common in the first encounters, such as short wooden clubs and metal maces, as well as all sorts of short knives and even brass knuckles (see trench raiding). As the war progressed, better gear was issued, and the improvised arms were discarded.
Pump shotguns were mainly used by American soldiers in the Western front. Rather than a single, high velocity bullet, a shotgun fires a larger number of metal balls, called shot. While each shot pellet causes far less damage than a rifle round, the standard load of 9 .34 caliber (US designation: "00" or "double ought") buckshot was likely to cause multiple serious wounds at close range, thus increasing the odds of a disabling wound. A shotgun loaded with buckshot was a formidable weapon in short range combat--enough so that Germany lodged a formal protest against their use on 14 Sept. 1918, stating "every prisoner found to have in his possession such guns or ammunition belonging thereto forfeits his life" (though this threat was apparently never carried out). The US military began to issue pump shotguns specially modified for combat, called "trench guns". These had shorter barrels than sporting shotguns, longer magazines, no choke, and were often outfitted with heat shields around the barrel and bayonet lugs which used M1917 Bayonets. Descendants of the "trench gun" still exist today in the form of the combat shotgun and its cousin the riotgun. ANZAC and some British soldiers were also known to use sawn-off double barrel shotguns in trench raids, because of their portability, effectiveness at close range, and ease of use in the confines of a trench. This practice was not officially sanctioned, and the shotguns used were invariably civilian sporting shotguns, suitably altered for their new purpose.
The grenade came to be the primary infantry weapon of trench warfare. Both sides were quick to raise specialist bombing squads. The grenade enabled a soldier to engage the enemy indirectly (without exposing himself to fire), and it did not require the precise accuracy of rifle fire in order to kill or maim. The Germans and Turks were well equipped with grenades from the start of the war, but the British, who had ceased using grenadiers in the 1870s and did not anticipate a siege war, entered the conflict with virtually none, such that soldiers had to improvise bombs with whatever was available. By late 1915, the British Mills bomb had entered wide circulation, and by the end of the war 75 million of them had been used.
[modifier] Casques
During the first year of the First World War, none of the combatant nations equipped their troops with steel helmets. Soldiers went into battle wearing simple cloth or leather caps that offered virtually no protection from the damage caused by modern weapons. German troops were wearing the traditional leather Pickelhaube (spiked helmet), with a covering of cloth to protect the leather from the splattering of mud. Once the war entered the static phase of trench warfare, the number of lethal head wounds that troops were receiving from fragmentation increased dramatically.
The French were the first to see a need for greater protection and began to introduce steel helmets in the summer of 1915. The Adrian helmet (designed by August-Louse Adrian) replaced the traditional French kepi and was later adopted by the Belgian and Italian armies.
At about the same time the British were developing their own helmets. The French design was rejected as not strong enough and too difficult to mass-produce. The design that was eventually approved by the British was the Brodie helmet (designed by John L. Brodie). This had a wide brim to protect the wearer from falling objects, but offered less protection to the wearer's neck. When the Americans entered the war, this was the helmet they chose.
The traditional German pickelhaube was replaced by the Stahlhelm or "coal-scuttle helmet" in 1916. Some elite Italian units used a helmet derived from ancient Roman designs.
None of these standard helmets could protect the face or eyes, however. Special face-covers were designed to be used by machine-gunners, and the Belgians tried out goggles made of louvres to protect the eyes.
[modifier] mitraillette
The machine gun is perhaps the signature weapon of trench warfare, with the image of ranks of advancing infantry being scythed down by the withering hail of bullets. The Germans embraced the machine gun from the outset—in 1904, every regiment was equipped with one machine gun—and the machine gun crews were the elite infantry units. Modèle:Citation needed After 1915, the MG 08/15 was the standard-issue German machine gun; its number entered the German language as an idiomatic expression for "dead plain". At Gallipoli and in Palestine the Turks provided the infantry, but it was usually Germans who manned the machine guns.
The British High Command were less enthusiastic about machine gun technology, supposedly considering the weapon too "unsporting" and encouraging defensive fighting, and they lagged behind the Germans in adopting the weapon. Field Marshall Sir Douglas Haig is quoted as saying in 1915 "The machine gun is a much overrated weapon; two per battalion is more than sufficient"[1], which resulted in record numbers of British causualties using these tactics. [[2]] In 1915 the Machine Gun Corps was formed to train and provide sufficient heavy machine gun teams. It was the Canadians that made the best practise, pioneering area denial and indirect fire (soon adopted by all Allied armies) under the guidance of former French Army Reserve officer Major General Raymond Brutinel. To match demand, production of the Vickers machine gun was contracted to firms in the United States. By 1917, every company in the British forces were also equipped with four Lewis light machine guns, which significantly enhanced their firepower.
The heavy machine gun was a specialist weapon, and in a static trench system was employed in a scientific manner, with carefully calculated fields of fire, so that at a moment's notice an accurate burst could be laid upon the enemy's parapet or at a break in the wire. Equally it could be used as light artillery in bombarding distant trenches. Heavy machine guns required teams of up to eight to move them, maintain them and keep them supplied with ammunition.
[modifier] Mortiers
Mortars, which lobbed a shell a relatively short distance, were widely used in trench fighting for harassing the forward trenches and for cutting wire in preparation for a raid or attack. In 1914, the British fired a total of 545 mortar shells. In 1916, they fired over 6,500,000 shells.
The main British mortar was the Stokes mortar, which was the precursor of the modern mortar. It was a light mortar, but was easy to use, and capable of a rapid rate of fire by virtue of the propellant cartridge being attached to the shell. To fire the Stokes mortar, the round was simply dropped into the tube, where the cartridge was ignited automatically when it struck the firing pin at the bottom.
The Germans used a range of mortars. The smallest were grenade-throwers (Granatenwerfer) which fired "pineapple" bombs. Their medium trench-mortars were called mine-throwers (Minenwerfer), dubbed "minnies" by the British. The heavy mortar was called the Ladungswerfer which threw "aerial torpedoes", containing a 200 lb (90 kg) charge, over 1000 yards. The flight of the missile was so slow and leisurely that the men on the receiving end could make some attempt to seek shelter.
[modifier] Artillerie
Artillery dominated the battlefield of trench warfare in the same way that air power dominates the modern battlefield. An infantry attack was rarely successful if it advanced beyond the range of its supporting artillery. In addition to bombarding the enemy infantry in the trenches, the artillery would engage in counter-battery duels to try to destroy the enemy's guns.
Artillery mainly fired fragmentation, high explosive, or, later in the war, gas shells. The British experimented with firing thermite incendiary shells to set trees and ruins alight.
Artillery pieces were of two types: guns and howitzers. Guns fired high-velocity shells over a flat trajectory and were often used to deliver fragmentation and to cut barbed wire. Howitzers lofted the shell over a high trajectory such that it plunged into the ground. The biggest artillery were usually howitzers. The German 420 mm howitzer weighed 20 tons and could fire a one-ton shell over 10 km.
A critical feature of modern artillery pieces was the hydraulic recoil mechanism which meant the gun did not need to be re-laid (re-aimed) after each shot. Initially each gun would need to register its aim on a known target, in view of an observer, in order to fire with precision during a battle. The process of gun registration would often alert the enemy an attack was being planned. Towards the end of 1917, artillery techniques were developed enabling fire to be delivered accurately without registration.
[modifier] Gaz
Voir l'article détaillé: Gaz World War I
Tear gas was first employed in August 1914 by the French, but this could only disable the enemy. In April 1915, chlorine was first used by Germany at the Second Battle of Ypres. A large enough dose could kill, but the gas was easy to detect by scent and sight. Those that were not killed on exposure could suffer permanent lung damage.
Phosgene, first used in December 1915, was the ultimate killing gas of World War I—it was 18 times more powerful than chlorine and much more difficult to detect. However, the most effective gas was mustard gas, introduced by Germany in July 1917. Mustard gas was not as fatal as phosgene, but it was hard to detect and lingered on the surface of the battlefield and so could inflict casualties over a long period. The burns it produced were so horrific that a casualty resulting from mustard gas exposure was unlikely to be fit to fight again. Only 2% of mustard gas casualties died, mainly from secondary infections.
The first method of employing gas was by releasing it from a cylinder when the wind was favourable. Such an approach was obviously prone to miscarry if the direction of the wind was misjudged. Also, the cylinders needed to be positioned in the front trenches where they were liable to be ruptured during a bombardment. Later in the war, gas was delivered by artillery or mortar shell.
[modifier] Barbelé
The use of barbed wire was decisive in slowing infantry travelling across the battlefield. Without it, fast moving infantry (or cavalry) might cross the lines and reach the enemy machine gun posts and artillery. Slowed down by the barbed wire, they were much more likely to be shot down by the machine guns or infantry men. Liddell Hart identified barbed wire and the machine gun as the elements that had to be broken to regain a mobile battlefield.
Wiring was usually done at night in active sectors, and the screw picket invented during the war helped decrease the amount of noise working parties would create.
[modifier] Aviation
The fundamental purpose of the aircraft in trench warfare was reconnaissance and artillery observation. Aerial reconnaissance was so significant in exposing movements, it has been said the trench stalemate was a product of it. The role of the fighter was to protect friendly reconnaissance aircraft and destroy those of the enemy, or at least deny them the freedom of friendly airspace. This involved achieving air superiority over the battlefield by destroying the enemy's fighters as well. Spotter aircraft would monitor the fall of shells during registration of the artillery. Reconnaissance aircraft would map trench lines (first with hand-drawn diagrams, later photographs), monitor enemy troop movements, and locate enemy artillery batteries so that they could be destroyed with counter-battery fire. More ingenious pilots would carry bricks with them when going on flights in order to drop on the enemy.
[modifier] Mines
All sides would engage in vigorous mining and counter-mining duels. The dry chalk of the Somme was especially suited to mining, but with the aid of pumps, it was also possible to mine in the sodden clay of Flanders. Specialist tunnelling companies, usually made up of men who had been coal miners in civilian life, would dig tunnels under no man's land and beneath the enemy's trenches. These mines would then be packed with explosives and detonated, producing a large crater. The crater served two purposes: it could destroy or breach the enemy's trench and, by virtue of the raised lip that they produced, could provide a ready-made "trench" closer to the enemy's line. When a mine was detonated, both sides would race to occupy and fortify the crater.
If the miners detected an enemy tunnel in progress, they would often drive a counter-tunnel, called a camouflet, which would be detonated in an attempt to destroy the other tunnel prematurely. Night raids were also conducted with the sole purpose of destroying the enemy's mine workings. On occasion, mines would cross and fighting would occur underground.
The mining skills could also be used to move troops unseen. On one occasion a whole division was moved through interconnected workings and sewers without German observation.
The British detonated a number of mines on July 1, 1916, the first day of the Battle of the Somme. The largest mines—the Y Sap Mine and the Lochnager Mine—each containing 24 tons of explosives, were blown near La Boiselle, throwing earth 4,000 feet into the air.
At 5.10 AM on June 7, 1917, 19 mines were detonated by the British to launch the Battle of Messines. The average mine contained 21 tons of explosive and the largest, 125 feet beneath St. Eloi, was twice the average at 42 tons. The combined force of the explosions was supposedly felt in England. As the Chief of Staff of the British Second Army, General Sir Charles Harrington, commented on the eve of the battle:
- I do not know whether we shall change history tomorrow, but we shall certainly alter the geography.
The craters from these and many other mines on the Western Front are still visible today. Three further mines were laid for Messines but were not detonated as the tactical situation had since changed. One blew during a thunderstorm in 1955; the other two remain to this day.
[modifier] Lances-flammes
Les allemandes employerent des lances-flammes (Flammenwerfer) durant la première guerre mondiale, mais la technologie n'était pas encore mature, ainsi ils servaient plus à propager la terreur qu'à provoquer des pertes sérieuses.
[modifier] bataille de tranchée
[modifier] Strategie
The fundamental strategy of trench warfare was to defend your own position strongly while trying to achieve a breakthrough into the enemy's rear. The effect was to end up in attrition; the process of progressively grinding down the opposition's resources until, ultimately, they are no longer able to wage war. This did not prevent the ambitious commander from pursuing the strategy of annihilation—the ideal of an offensive battle which produces victory in one decisive engagement. The Commander in Chief of the British forces, General Douglas Haig, was constantly seeking a "breakthrough" which could then be exploited with cavalry divisions. His major trench offensives—the Somme in 1916 and Flanders in 1917—were conceived as breakthrough battles but both degenerated into costly attrition. The Germans actively pursued a strategy of attrition in the Battle of Verdun, the sole purpose of which was to "bleed the French Army white". At the same time the Allies needed to mount offensives in order to draw attention away from other hard-pressed areas of the line.
[modifier] Tactique
The popular image of a trench warfare infantry assault is of a wave of soldiers, bayonets fixed, going "over the top" and marching in a line across no man's land into a hail of enemy fire. This indeed was the standard method early in the war and successful examples are few. The more common tactic was to attack at night from an advanced post in no man's land, having cut the barbed wire entanglements beforehand.
In 1917, the Germans innovated with the "infiltration" tactic where small groups of highly trained and well-equipped troops would attack vulnerable points and bypass strongpoints, driving deep into the rear areas. The distance they could advance was still limited by their ability to supply and communicate.
The role of artillery in an infantry attack was twofold: firstly in preparation by killing or driving off the enemy garrison and destroying his defences, and secondly in protecting the attacking infantry by providing an impenetrable "barrage" or curtain of shells to prevent an enemy counter-attack. The first attempt at sophistication was the "lifting barrage" where the first objective of an attack was intensely bombarded for a period before the entire barrage "lifted" to fall on a second objective farther back. However, this usually expected too much of the infantry, and the usual outcome was that the barrage would outpace the attackers, leaving them without protection. This resulted in the use of the "creeping barrage" which would lift more frequently but in smaller steps, sweeping the ground ahead and moving so slowly that the attackers could usually follow closely behind it.
Capturing the objective was half the successful battle—the battle was only won if the objective was held. The attacking force would have to advance with not only the weapons required to capture a trench but also the tools—sandbags, picks and shovels, barbed wire—to fortify and defend from counter-attack. The Germans placed great emphasis on immediately counter-attacking to regain lost ground. This strategy cost them dearly in 1917 when the British started to limit their advances so as to be able to meet the anticipated counter-attack from a position of strength.
[modifier] Communications
The main difficulty faced by an attacking force in a trench battle was reliable communications. Wireless communications were still in their infancy, so the available methods were telephone, semaphore, signal lamps, carrier pigeons and runners, none of which were particularly reliable. Telephone was the most effective, but the lines were extremely vulnerable to shell fire and so would usually be cut early in a battle. In an attempt to counter this, telephone lines would be laid in a ladder pattern to provide multiple redundant paths. Flares and rockets were used to signal an objective was reached or to call for prearranged artillery support.
It was not unusual for a battalion or brigade commander to wait two or three hours for word on the progress of an attack, by which time any decision made based on the message would probably be long out of date. A similar period would pass when transferring the news to the division, corps and army headquarters. Consequently, the outcome of many trench battles was decided by the company and platoon commanders in the thick of the fighting.
[modifier] Obsolescence
With the withdrawal of Russia from World War I, the Germans were able to reinforce their western front with troops from the eastern front. This allowed them to take units out of the line and train them in new methods and tactics as stormtroopers (sturmtruppen). The new methods involved men rushing forward in small groups using whatever cover was available and laying down covering fire for other groups in the same unit as they moved forward. The new tactics (intended to achieve surprise by disrupting entrenched enemy positions) were to bypass strongpoints and attack the weakest parts of an enemy's line. Additionally, they acknowledged the futility of managing a grand detailed plan of operations from afar, opting instead for junior officers on the spot to exercise initiative. These tactics proved very successful during the German 1918 Spring Offensive against Allied forces.
The static trench battle was broken as the tank developed. Conceived to give infantry armor against machine guns, it also added mobility. While not effectively employed at first, tanks had tremendous morale effects on German troops in the closing stages of the war on the Western front.
The Americans played a major role in breaking through the trenches. General John Pershing saw trench warfare as useless and costly, and ordered the men he commanded to launch both direct and surprise assaults on the enemy trenches, using artillery and infantry fire to strike targets up close.
During the last 100 days of World War I, the British forces broke through the German trench system and harried the Germans back toward Germany using infantry supported by tanks and close air support. Between the two world wars these techniques were used by J.F.C. Fuller and B.H. Liddell Hart to develop theories about a new type of warfare. The ideas were picked up by the Germans, who developed them further and put them into practice with the use of Blitzkrieg.
The stunning victories by the Germans early in World War II using blitzkrieg showed that fixed fortifications like the Maginot Line could be bypassed. The amphibious landing (combined with air-cover and landings behind the line) by the Western Allies in 1944 broke through the incomplete Atlantic Wall with relative ease. The fight inland through the bocage proved far more of an obstacle than the fixed fortifications of the Atlantic Wall.
Combined arms tactics (where infantry, artillery, armour and aircraft operate in close cooperation) made trench warfare obsolete. The foundation of modern land warfare lies in semiautonomous small teams (such as the fire team) and places a large emphasis on rapid communication and allowing smaller units to exercise initiative.
This is not to say that entrenchment is redundant. It is still a valuable method for reinforcing natural obstacles to create a line of defence. At the start of the Battle of Berlin, the last major assault of World War II, the Russians attacked over the river Oder against German troops dug in on the Seelow Heights, which are about 50 km east of Berlin. Entrenchment allowed the Germans, who were massively outnumbered, to survive a barrage from the largest concentration of artillery in history; it also allowed the Germans to inflict tens of thousands of casualties on the Soviets, thanks to the marshy land which lay between the river and the heights, before being driven west.
[modifier] guerres de tranchée récentes
Trench warfare has been very infrequent since the end of World War I. When two large armoured armies meet, the result has generally been mobile warfare of the type which developed in World War II.
However, trench warfare reemerged in the latter stages of the Korean War (1950-53) and in some locations and engagements in the Vietnam War (1964-75).
During the Cold War, NATO forces routinely trained to fight through extensive works called "Soviet-style trench systems", named after the Warsaw Pact's complex systems of field fortifications, an extension of Soviet field entrenching practices for which they were famous in their Great Patriotic War.
The most cited example of trench warfare after World War I was the Iran-Iraq War, in which both armies had a large number of infantry with modern small arms, but very little armour, aircraft or training in combined weapons. The result was very similar to World War I with trenches and chemical warfare used.
Another example of trench stalemate was the Eritrean-Ethiopian War of 1998–2002. The front line in Korea and the front lines between Pakistan and India in Kashmir are two examples of demarcation lines which could become hot at any time. They consist of kilometers of trenches linking fortified strongpoints and in Korea surrounded by millions of land mines.
[modifier] Références
- Dupuy, Trevor N., Evolution of Weapons and Warfare.
- Dupuy, Trevor N., Numbers, Predictions, and War. Bobbs-Merrill, 1979?
- Fitzsimmons, Bernard, general editor (with Bill Gunston, Ian Hogg, & Anthony Preston). Encyclopedia of 20h Century Weapons and Warfare. 24 volumes.
- Gudmundsson, Bruce I. Stormtroop Tactics: Innovation in the German Army, 1914-1918 (1989)
- Haber, L. F. The Poisonous Cloud: Chemical Warfare in the First World War (1986);
- Herwig, Holger H. Operation Michael: The "Last Card" 2001 German Spring Offensive in 1918
- Palazzo, Albert. Seeking Victory on the Western Front: The British Army and Chemical Warfare in World War I (2000)
- Sheffield, G. D. Leadership in the Trenches: Officer-Man Relations, Morale and Discipline in the British Army in the Era of the First World War (2000)
- Smith, Leonard V. Between Mutiny and Obedience. The Case of the French Fifth Infantry Division during World War I (1994)
- Winter, Denis. Death's Men: Soldiers of the Great War. 1978, ISBN 0-14-016822-2
- Canfield, Bruce N. Give Us More Shotguns! American Rifleman, May 2004.
[modifier] Voir aussi
[modifier] articles connexes
- (en) Passchendaele
- (fr) Hartmannswillerkopf
- (fr) Fil de fer barbelé
[modifier] Liens externes
- (en) BBC reconstruction of life in the trenches
- (en) The Diggers
- (en) Information on Australian World War 2 Fortifications
Catégorie:Place forte Catégorie:Stratégie militaire Catégorie:Type de guerre
