| Landslide is one of the main types of geological hazards in mountainous highway, As the highway linking Dazhou and Xuanhan is declared the city fast trunk road, along the line of geological disasters is developed, Chaqishan ancient landslide is an important geological disasters along the disasters. The landslide deformation after long-term evolution, the shape characteristic of the landslide have changed significantly, with some hidden and difficult to find, resulting in insufficient understanding in the exploration stage, along with the highway excavation the landslide deformation phenomena appear obvious. Therefore, to carry out understanding of the basic characteristics of the landslide and stability evaluation, provide the basis for the engineering design of the treatment, to ensure the highway safety construction and later safe operation has important practical significance, similar to the ancient landslide deformation evolution, stability analysis and treatment has a certain reference value.Based on the geological environmental conditions of the landslide area and the characteristics of the landslide structure, the focus of the landslide deformation and evolution of the characteristics of the system of research, The genetic mechanism and deformation evolution of the ancient landslide are analyzed by the method of geology mechanics, According to the geological analysis and numerical simulation method to study the landslide in highway excavation and heavy rain under the action of mechanism, Qualitative and quantitative methods are used to evaluate the overall stability of the landslide, so as to put forward the reasonable control measures, the control engineering is simulated by numerical simulation, and the stability of the landslide is calculated, The results obtained are as follows.(1)The slope of the study area is in the middle inclined slope of the sandstone and mudstone, and a set of plane "X" type joint is developed in the slope body, The rear part of the slope is long under the influence of the collapse accumulation loading, and the slope is gradually formed through the formation of the sliding surface, and the slope main failure mode is sliding and fracturing, formed Chaqishan ancient landslide.(2) The landslide deformation evolution controlled by Rainstorm and gully erosion, has been undergoing a slow creeping deformation, formed multi-level Valley steep arc landform, which Point to the valley, The deformation degree of the right area was significantly stronger than the left.(3) Road excavation leads to landslide revival, The length of the slide block and the sliding force,the stability of the landslide is decreased after highway excavation. In the middle of the landslide occurred transverse tensile cracks and lateral echelon fracture, At the same time in the highway excavation section exposed in the slip zone and the mirror surface scratches, the overall stability will be further reduced when the slide block be completely cut off, There is a serious security risk to the safety construction and the later period of the highway.(4) Using Flac3 D numerical simulation of landslide without excavation, excavation, two excavation in the natural and heavy rain conditions,analysis of stress, displacement, plastic deformation zone, shear strain increment, Simulation results show that: Along with the excavation step by step, the landslide stress field method is changed, the displacement of landslide is gradually increasing, and there is a significant increase in the area, and in rainstorm further intensified; in the process of highway excavation, landslide plastic deformation occurs in the whole process and along with the gradual excavation, plastic deformation and plastic damage range increased, shear strain increment penetration area of shear strain increment the penetrating the whole slope under excavation and heavy rains.(5) Limit equilibrium method is the most commonly used method for landslide stability calculation, In this paper, the transfer coefficient method is used to calculate the stability of landslide, and the slope/W module in Geo-studio professional software developed by Canada Company is used as a platform, The stability of the landslide is calculated and analyzed by using Morgenstern-Prince, Janbbu, Bishop and the Swedish slice method. The calculation results show that the landslide is in a stable state under natural conditions and heavy rain conditions, after excavation, the landslide is in an unstable state under the condition of natural condition and heavy rain, and the overall stability of the rainstorm is lower.(6) Based on the calculation results of the residual sliding force of the landslide, combined with the characteristics of landslide deformation and highway excavation, the control scheme of landslide is proposed, which is anti slide pile + anchor frame beam and drainage ditch, and Carry out partial design. Use Flac3 D numerical simulation to simulate the control engineering, And according to the stability of the landslide after calculation shows that the control engineering is reasonable, and it can achieve the purpose of this study. |
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