An Experimental Investigation On Evolution Of Landslide Anchorage System Under Sudden Drop Of Reservoir Water Using Transparent Soil

The sudden drop of reservoir water level causes landslide geological disaster,which poses a great threat to the safety of people's lives and property and the safe operation of the reservoir.The installation of umbrella anchor will improve the stability of landslide and change the sliding evolution process.Based on the transparent soil test technology,the paper studies the evolution process,characteristics and influencing factors of landslide and landslide anchorage system under the condition of sudden drop of reservoir water level.The main research results are as follows:(1)Through the experiment of landslide evolution under the condition of sudden drop of reservoir water level,the results show that the internal horizontal seepage of the slope under the condition of sudden drop of reservoir water level,and the seepage near the slope is parallel to the slope.The evolution law of landslide under the condition of sudden drop of reservoir water level has the characteristics of sliding from shallow layer to whole,from front edge to middle and then to back edge.The shallow sliding surface is linear,while the deep sliding surface is circular,and the evolution conforms to the typical progressive traction failure mode.The evolution stage can be divided into three stages: shallow low-speed sliding,overall fast sliding and low-speed sliding to slope stability.The stability of model slope is smaller than that of non cohesive soil slope.(2)Through the experiment of landslide anchorage system evolution under the condition of sudden drop of reservoir water level,it is found that umbrella anchor has good reinforcement effect on soil landslide.The evolution process of landslide anchorage system is closely related to the arrangement of anchor bolt.The back edge and top of slope will not slip and instability,and sliding will not be backward edge The deep sliding forms the through sliding surface,which is nearly line,and the evolution still conforms to the progressive traction failure mode,and the failure mode of the landslide anchorage system is the whole sliding caused by the soil sliding between anchors and under anchors.Meanwhile,the test shows that the placement of anchor will lead to the decrease of the compactness of the shallow soil,and the shallow sliding will easily occur when the water level of the reservoir drops suddenly.Therefore,the shallow soil within the influence range shall be reinforced after the anchor is implanted.The starting sliding part is generally under the anchor bolt near the slope toe.Therefore,the soil mass under the anchor bolt near the slope toe should be strengthened.The theoretical formula of stability coefficient under sudden drop of water level of the non cohesive soil landslide anchorage system is derived.It is found that the theoretical calculation value of the stability of the landslide anchorage system is equivalent to the stability coefficient reflected by the test data.(3)The test also shows that the evolution process of the landslide anchorage system is greatly affected by the anchorage mode,followed by the slope angle,and the decline rate of the reservoir water level has relatively little effect.The specific performance is as follows The stability of the landslide anchorage system decreases rapidly with the increase of the slope angle.When the slope angle increases to a certain value,the decrease of the stability will decrease rapidly.The smaller the spacing of the anchor,the smaller the landslide-The more stable the anchorage system is,the smaller the sliding speed and amount will be.At the same time,the initial sliding time of the landslide anchorage system and the failure time of the anchor near the foot of the slope will delay with the reduction of the anchorage distance.The anchor rod near the slope toe has a great influence on the stability of the landslide anchorage system,so it is necessary to reduce the spacing of the anchor rod near the slope toe in the construction process;the greater the falling speed of the reservoir water level,the worse the stability of the landslide anchorage system,the greater the sliding speed and sliding amount,and the greater the falling speed of the reservoir water level,the easier the landslide anchorage system is to be damaged.There are 60 pictures,17 tables and 136 references in this paper.