暗挖工程中管幕支护施工引起的地层位移

Analysis of ground displacement due to pipe roof installation

随着城市化进程的推进,地下空间的开发和利用越来越受到人们的重视。管幕法作为一种有效的暗挖支护方式,越来越多的用于城市地下工程开挖施工。管幕施工中常用的技术主要有顶管法和夯管法。管幕施工造成的地层位移会对周围环境产生影响。探讨了管幕施工对地层的挤土扰动对环境的影响。考虑土体的剪胀特性和塑性变形,推得了在管挤入过程中周围土体内的位移场和应力场表达式,利用叠加法推导了管幕夯进引起的土体位移的理论解,研究了地层竖向位移对土层参数、初始应力、埋深等参数的敏感性,并分析了管间距和管的布置形式对管幕引起土体位移的影响。

As an effective supporting measure in underground excavation,the pipe roof method has been widely used.In the construction process of pipe roofs(ramming or jacking method),the surrounding soil layer is disturbed and the ground deformation is produced to affect the environment.On the basis of plastic mechanics,considering the dilatancy of soil,formulas for stress and displacement distribution produced by pipe roof construction in infinite space with cylindrical cavity expansion were obtained.Expressions of stress and displacement field in half space were deduced by use of the image method.The sensibilities of soil parameters,buried depth,initial stress and relative buried depth to vertical displacement were analyzed.It is shown that the buried depth,initial stress are the main factors affecting the deformation.