英语翻译Soft-ground tunneling .Some tunnels are driven wholly or mostly through soft material .In very soft ground ,little or no blasting is necessary because the material is easily excavated .At first ,forepoling was the only method for building

英语翻译Soft-ground tunneling .Some tunnels are driven wholly or mostly through soft material .In very soft ground ,little or no blasting is necessary because the material is easily excavated .At first ,forepoling was the only method for building
英语翻译
Soft-ground tunneling .Some tunnels are driven wholly or mostly through soft material .In very soft ground ,little or no blasting is necessary because the material is easily excavated .
At first ,forepoling was the only method for building tunnels through very soft ground .Forepoles are heavy planks about 5 feet ( 1.5 meters ) long and sharpened to a point .They were inserted over the top horizontal bar of the bracing at the face of the tunnel .The forepoles were then driven into the ground of the face with an outward inclination .After all the roof poles were driven for about half of their length ,a timber was laid across their exposed ends to counter any strain on the outer ends .The foreples thus provided an extension of the tunnel support ,and the face was extended under them .When the ends of the forepoles were reached ,new timbering support was added ,and the forepoles were driven into the ground for the next advance of the tunneling .
The use of compressed air simplified working in soft ground .An airlock was built ,through which men and equipment passed,and sufficient air pressure was maintained at the tunnel face to hold the ground firm during excavation until timbering or other support was erected.

英语翻译Soft-ground tunneling .Some tunnels are driven wholly or mostly through soft material .In very soft ground ,little or no blasting is necessary because the material is easily excavated .At first ,forepoling was the only method for building
Soft-ground隧道掘进高线驱动的全部或大部分是通过柔软的材料.在很松软的地面,很少或根本没有爆破是必要的,因为这个材料容易挖掘.
起初,forepoling是唯一的方法,为建设隧道通过地面很软很重的厚木板.Forepoles大约5英尺(1.5米)长,加剧了一点.他们被注入到顶部单杠的支撑的面部隧道.当时的forepoles赶进了地面的脸和外表的心理倾向.毕竟屋顶极点被他们的大约一半的长度,木材被横穿他们结束针对任何紧张暴露在外面的结束.由此提供了foreples隧道支护的一种扩展,脸部延长下面去.当两端的forepoles达成的协议,支持,加入了新的理性化和forepoles被赶进了地面下前进的隧道.
使用压缩空气简化工作在松软的地面.建立了一种防范,通过这个人和设备通过了,和充足的空气压力维持在隧道举办地面公司面临的理性化开挖过程直到第一座架设或另外的支持.