降雨对无支挡结构下隧道-滑坡正交体系的作用机理研究

Research on the Influence Mechanism of Rainfall for the Tunnel-Landslide Orthogonal Systerm Without the Supporting Structure

通过大型地质力学模型试验,研究在无支挡结构下降雨对隧道-滑坡正交体系的作用机理。主要研究不同降雨阶段,隧道-滑坡正交体系下隧道纵向应变的变化特征及隧道不同横断面环向应力变化特点,并重点分析在不同降雨阶段,不同位置及其不同横断面滑体的位移变化特征。试验结果表明:(1)降雨可导致坡体横断面断裂而出现新的滑移面,从而导致坡体失稳。(2)在隧道-滑坡正交体系下,随着雨水的下渗及滑体土样含水率不断增大,隧道局部应变有明显突变,且山侧纵向应变比河侧应变要大。(3)在隧道-滑坡正交体系下,降雨使得隧道环向应力呈不均匀变化:隧道的底部应力大于顶部应力,山侧应力大于河侧应力,表明降雨可导致滑体蠕动或局部滑移,引起隧道不均匀受力及变形,这对隧道结构的安全非常不利。本次试验可为雨水充沛区的滑坡及隧道抗滑设计提供一定参考。

Rainfall is one of the important factors that induce landslide sliding and landslide stabil- ity.At present,the research on the influence of rainfall on the tunnel landslide orthogonal system without the supporting structure is still lacking.In order to study the action mechanism of rainfallon the tunnel landslide orthogonal system under different intensity of rainfall,and study the char- acteristics of slope deformation and the stress characteristics of the tunnel without the supporting structure, the influence mechanism of rainfall for the Tunnel-Landslide （）rthogonal system by large geological mechanics simulation model test is researched. With the four different stages of rainfall,the changing characteristics of longitudinal of tunnel and the variation characteristics of circumferential stress of tunnel with different cross sections, and the changing characteristics of the displacement of the sliding body at different locations and different cross sections also are ana- lyzed.The results show that： （1） The rain can lead to the cross-sectional of slope broke,and form a new glide plane which result in the landslide slipped.（2） With the increasing of water content of sand,the strain of tunnel has obviously sudden changed,and the longitudinal strain of tunnel near the mountain is bigger than the longitudinal strain of tunnel near the river. （3）Rainfall makes stress of the tunnel uneven change^And the stress of tunnel bottom is greater than the stress of the top, the stress near the mountain is larger than the stress near the river under the tunnel land slide orthogonal system,and shows that necessary drainage measures are indispensable. And it is indicated that the rainfall can cause the movement of the sliding body, cause the uneven stress and deformation of the tunnel,which is very unfavorable to the safety of the tunnel structure.This ex- periment can provide some reference for the landslide and tunnel anti slide design in the abundant water area.