Large Physical Model Test On The Interaction Between The Landslide And Anchor Anti-slide Pile

As the important retaining structure, anchor anti-slide pile has played a very positive role in large and medium-sized landslide treatment project in recent years. However, its theoretical research lagged far behind the engineering practice leaded to sacrificing engineering investment in actual application process. The research achievements in this thesis are funded by the National Natural Science Funds and Land resources investigation projects of China geological survey. Various model tests on anchor anti-slide pile were carried out and the force, deformation and destruction of anchor anti-slide pile were studied from a number of angles. Based on the experimental studies, according to existed algorithm, tensile calculation formula of anchor is presented. The main research achievements in this thesis are as follows:(1) Photoelastic test on anchor anti-slide pile technology, small scale model test and large scale model test were carried out and the application of anchor anti-slide pile technology in loess landslide treatment project is studied deeply, which provides a basis for the application of anchor anti-slide pile in landslide disaster treatment engineering.(2)Deformation characteristics and failure mechanism of anchor anti-slide pile under the action of landslide thrust is studied and three possible failure modes of anchor anti-slide in soil landslide are revealed. They are pile plastic hinge damage, anchor failure and soil around the pile plastic failure.(3) Through analyzing the comparison of pressures, pressure distribution forms of anchor anti-slide piles in different conditions are obtained and their values, distribution collection degrees and the relations with embedded depth of piles are calculated.(4) Through analyzing strain of steel bar in anchor anti-slide piles,the distributions of bending moment and their values and distribution collection degrees are offered.(5) According to several tests, embedded depth of anchor anti-slide piles in different conditions are studied and their reasonable numerical range are pointed out.(6) According to the anchor reinforcement strain and numerical analysis of reinforcement meters, the force to rows of anchors gradually increases gradually from top to bottom. That is to say, the force to the lowest row of anchors is the largest and these anchors share more landslide thrust. Then the force from bottom to top gradually decreases and its proportional relations are deduced.(7) Through analyzing of the results of photoelastic test, with the increasing of load, the proportion of landslide thrust shared by anchor anti-slide piles increases within the scope of the bearable tension to anchor anti-slide pile and has an intently relations of embedded depth of the pile. The proportion is large if embedded depth is small and small if embedded depth is large. In addition, with the increasing of the stiffness of pile, the proportion of anchor tension to landslide thrust reduces accordingly.(8) For single anchor anti-slide pile, shearing deformation of anchor occurred near the sliding surface, which causes the fixed segment of the pile curved upward and the free segment curved down. For multi anchors anti-slide pile, this phenomenon is not obvious.(9) For ordinary anti-slide pile and single anchor anti-slide pile, there will exist disengaging area in certain range near the sliding surface when slope failure occurs. For multi anchors anti-slide pile, this obvious phenomenon can hardly be detected.(10) For anchor anti-slide pile placed in the soil, the pile foot can be designed by free bearing.(11) According to the results of model test and existed algorithm, structural mechanics calculation method of anchor tensile is calculated.(12) When setting up anti-slide piles in the soil slop, multi anchors anti-slide piles should be the first choice if condition permits. Multi anchors anti-slide piles can not only increase the sliding resistance greatly and reduce internal force and deformation of the piles, but also reduce the project investment greatly and decrease construction difficulty accordingly.