Experimental Study On Bearing Capacity And Group Anchor Effect Of Inflatable Anchors In Clay

China is widely distributed in soft ground area,with inflatable anchor bearing performance,strong anchoring force can be provided immediately,Recyclable use the advantages,has a broad application prospect in ocean engineering and soft ground area.Many scholars have studied the aerated anchor at home and abroad,and obtained a lot of research results,but there is no engineering application example of the anchor bolt in the clay stratum of China.The bearing characteristics and the anchorage mechanism are not clear.Therefore,as a new type of anchor,it is necessary to study it in the strata and environment that have not yet been applied.This paper based on previous studies,using the method of indoor model test,carried out exploratory research on cyclic load bearing characteristics,inflatable anchor in clay soil in different experimental factors under the condition of bearing capacity and displacement characteristics,anchor group effect,the main research contents and results are as follows:(1)Based on the extensive investigation and research,the model of pneumatic anchor rod and a set of model test device for single anchor and group anchor uplift test are developed.(2)To carry out research on deformation characteristics of inflatable anchor expansion section,obtained under different pressure inflatable anchor end expansion section of equivalent diameter variation;carry out different depth,air pressure,filling water content under the condition of inflatable anchor pullout test: the buried depth increases,increasing the ultimate bearing capacity.Due to the influence of end expansion period,the ultimate bearing capacity has been greatly improved,its bearing capacity accounted for 45%~51.8%;gas pressure is the biggest factor affecting the ultimate bearing capacity,in a certain pressure range,pressure increase of inflatable anchor can effectively improve the performance of inflatable anchor anchor;inflatable anchor in moisture content close to clay the formation of liquid limit still has higher bearing capacity.Based on the nonlinear least square method,the experimental data are fitted to obtain the distribution law of the Q-S curve of the aerated anchor bolt.(3)Inflatable anchor in clay Q-S curve can be divided into elastic,elastic-plastic and plastic stages;through the analysis of loading unloading test Q-SE,Q-SP curve,the cut-off loads were 23.5% times and 83.5% times of Qu.(4)Carried out the cyclic loading test,discusses the evolution of inflatable anchor and displacement load under cyclic loading conditions,the results show that in a certain range of memory in a minimum number of cyclic loading.When the cyclic loading frequency is less than the value,and the accumulated settlement displacement increases with increasing number of cycles,cumulative settlement displacement convergence.Near to the limit load conditions of cyclic loading cumulative displacement convergence.(5)The uplift test of anchor group is carried out,and the double anchor increases with the increase of distance and the carrying capacity is weakened,and the peak point spacing is Ru=6.84 D.The contrast uplift test of the three anchor and the four anchor under the condition of spacing Ru shows that the form of the four anchor(rectangle)is better than the three anchor(triangle)arrangement form the bearing capacity and the displacement control.(6)Based on the principle of limit equilibrium analysis,the calculation model of the bearing capacity of aerated anchor is established.According to the pullout of typical clay structure and inflatable anchor pullout analysis of fracture surface morphology characteristics of analogy in shallow inflatable anchor in clay is horn shaped,and using the numerical analysis software,the estimation formula of ultimate bearing capacity of inflatable anchor derived by Qu.