Simulation Of Umbrella Anchor And Rock Interaction Characteristics Under Water Storage Conditions

In this paper,the geological conditions and water storage conditions of the slope of the Mei Hydroelectric Power Station reservoir are used as the background for the study.After equating the water storage process with the evolution of water content,a model test is used to study the influence of water level rise,rock structure,and number of anchors on the stability of the slope anchorage system and the deformation and evolution characteristics.After constructing the geological model of slope anchorage,two sets of model tests were designed: the first set of tests investigated the anchorage mechanism of umbrella-shaped anchors at different stages of landslide movement and determined the direction of stress sensor deployment in the anchorage system;the second set of orthogonal tests were designed using the rock formation inclination,moisture content and number of anchors as factors to analyze the deformation and evolution of the anchorage system.The study produced the following results.(1)The anchorage system stress analysis shows that the stability of the anchorage system decreases as the water level rises,the water content of the rock increases and the permeability changes;the stability of the anchorage system increases when the angle between the anchor and the rock surface increases from 0°to 20°,and the stability coefficient reaches the maximum at 20°;stability of the anchorage system increases as the anchor strength increases.(2)In the test,the axial force of the umbrella-shaped anchor was 20 s faster than that of ordinary anchor,and 2.4 times faster than that of ordinary anchor;the axial stress in the anchorage section was 25 s faster,and the value of axial stress in the stable anchorage system was twice that of ordinary anchor;the deformation of the umbrella-shaped anchor showed a transverse "S" type.The deformation of the anchor is 1.7 times that of a regular anchor.The umbrella anchor is characterized by rapid axial force generation,fast growth rate and high bending deformation.(3)The umbrella-shaped anchor mechanism is divided into two stages,when the slope is unstable but no displacement,the anchor mainly plays an anchoring role through the advantage of expanding the end of the umbrella blade;when the landslide destabilization begins to slide,the axial stress in the free section 1.3m rock body in the test is drastically reduced,but still remains at 0.7k Pa,indicating that the axial stress transmission is farther,because the anchoring system has a long extension range,fast axial stress transmission and small loss characteristics,so that the anchoring system and the free section rock body near the slippery surface of the rapid contactcombination to form a small-scale anchoring system to play a residual anchoring role.(4)The order of influence on the axial force in the orthogonal test is rock dip >number of rods > water content,the order of influence on the axial stress of the anchorage system is rock dip > number of rods > water content,and the order of influence on the strain is rock dip > number of rods > rock angle > water content.(5)The angle between the anchor rods and the rock formation has a significant effect on the axial force and the axial stress of the anchor solids in the anchorage system.As the angle between the anchor rods and the rock formation increases at0-20°,the axial stress and the axial force of the anchor solids gradually increase and reach the maximum at 20°.The number of anchor rods has a significant effect on the axial stress and the deformation of the anchor solids.(6)As the number of anchor rods increased,the group anchor effect was significant,the axial stress of the anchor solid and the axial force were close to zero,and the anchor rods failed;the deformation of the anchor rods gradually changed from transverse "S" type to transverse half "Y" type.(7)The orthogonal test showed that the best anchoring combination for the model was the use of a single umbrella anchor at an angle of 20 ° between the anchor and the rock formation for the landslide under unchanged water level.The papers have 111 figures,table 14.(8)At the beginning of the water storage process of the slope anchorage system,due to the prestressing effect of the anchor rod,the rock mass deforms into the slope.At this time,the axial force of the anchor rod gradually decreases with the rise of the water level;when the water level acts on the slope body for a period of time At this time,the sliding deformation of the slope body will increase with the increase of water level.With the process of water storage,the effective stress of the rock mass in the anchorage section gradually becomes smaller,and the anchoring force gradually decreases.