The Study On The Stability And Controlling Techniques Of Cutting Slope In Pseudo-soil

Most sections of mountainous highways are located on the natural slopes. Many slopes such as cutting, embankment, bridge foundation, tunnel inlet and outlet etc., will come into being in the process of construction, among which the pseudo-soil slopes which are composed of eluvium, completely weathered layer and strong weathered layer are the largest failure rate. It is rather difficult to accurately distinguish completely weathered layer and strong weathered layer, in addition which come into being in the same slope engineering at the same time, so it is necessary to research them as a whole. Pseudo-soil slope has different characters from the ones of soil slope and rock slope, so it is necessary to analyze its failure mechanism and put forward the corresponding control technology. Based on years of slope engineering surveying, designing and monitoring, combining with the projects of National Natural Science Foundation“Study on Evolution Mechanism of Soil and Rock Blending Landslide Under Fluid-solid Coupling Based on Energy Progressive Dissipation”(50878213/E080603),“Research of Highway Geological Disaster Monitoring and Forecasting Techniques for Western Area”(2003-318-802-01) which is supported by the Ministry of Transport, and“Study on Quick Repair Technology of Subgrade Subsidence and Collapse (2006-318- 802-111),“Study on the Stability of Metamorphosed Rock Series Weathered Layer Subgrade Slope in Guizhou Mountainous Areas(2006-318-802 -37)”, this paper carries out the researches as follows:1) Based on the analysis of highway slope failures in Guizhou and engineering control measures, this paper has summarized the engineering characteristic of highway pseudo-soil slope, chosen representative pseudo-soil slope testing spot, and developed engineering geology analysis.2) By on-the-spot work of developing the pseudo-soil slope failure induced by artificial rainfall experiments, the law of rainfall influence on pseudo-soil slope surface and body is analyzed.3) The governing equation of runoff on slope surface and the governing equation of slope runoff with consideration of inclination influence and corresponding definite conditions are illustrated. Combining on-the-spot work of developing artificial rainfall experiments, the mechanism of pseudo-soil slope failure caused by slope runoff is analyzed. 4) This paper has constructed a damage function which is suitable for pseudo-soil slope and derived the Mohr-Coulomb model based on damage function, and introduces the damage ratio to improve the Swedish circle method, which is applied to analyzes the mechanism of pseudo-soil slope failure caused by rainfall.5) The dynamic computational model of pseudo-soil slope permeability coefficient K has been brought up. The mathematical model for seepage-stress coupling damage behavior of pseudo-soil slope has been constructed. This model is applied to numerical simulation based on FLAC3D to analyze the mechanism of pseudo-soil slope failure caused by rainfall.6) On the basis of laboratory simulation tests and physical test, this paper researches the feasibility of slope slide face confirmation based on TDR technology; and it is proved that TDR technology applied in the actual engineering to confirm slide face is feasible, economical and advanced.7) Aimed to the engineering characteristic, the failure laws and failure mechanism of pseudo-soil slope, this paper puts forward the thought of stability control, and summaries the control measures for stability engineering control of pseudo-soil slope. In order to control slopewash and reduce rainfall infiltration, hallow pressure grouting technology has been developed and corresponding design program, design parameters and necessary apparatus have been put forward, which are applied in the multiple pseudo-soil slopes reinforcement. To control slope failure this paper has analyzed the anti-slide pile position arrangement influence on slope stability using failure energy analysis method, brought forward the simplified design process of anti-slide pile, advanced the design of anti-slide pile in aesthetic and coordination terms, come up with anti-slide pile with variable cross-section, deduced the calculation formula of anti-slide pile with variable cross-section displacement, and applied the result as above to the actual projects.