The Research Of Rock-socketed Pile Failure Mode Of Indoor Model Test And Finite Ele-ment Limit Analysis

Pile foundation has a long history of use in China.As the bearing capacity ofrock-socketed pile is very strong, test consuming high,it is difficult to destroy it in thestatic load test site.At present, for rock-socketed pile bearing characteristics and fail-ure modes have been not very full study abroad,characteristics in terms of carrying ca-pacity limits, shear stress distribution patterns, embedded depth and the best traits ofrock socketed pile bearing characteristics,etc. are for further study and improve-ment.Analyzed and summarized the calculation method of bearing capacity of rocksocketed pile in the stangard of different industries domestic,found the calculation me-thod of the present standard to rock socketed pile vertical bearing capacity of singlepile is based on a number of assumptions and have many empirical parameters; at thesame time, reference resources many domestic and foreign literature,inference the rockcharacteristics have great influence on rock socketed pile failure mode and bearing ca-pacity.According to the difference of embedded rock pile failure mode and bearing cha-racteristics of different rock characteristics, based on fully demonstrated on the subject,the specific work is as follows:①Make4groups of rock socketed pile model test of different pile diameter anddifferent rock properties and loading,according to a certain proportion, use sand, ce-ment and gypsum, talc powder to make bedrock, use2mm oil soil mixing layer in twolayers of bedrock to simulate the weak structural surface;②The paper presents the basis of finite element failure of rock socketed piles: theload displacement curves of mutation; the run through of plastic zone; finite elementcalculation does not converge;③Using the load increment method,which belongs to finite element limit analysismethod,to calculated on the indoor model test,and contrast the result of test results andfinite element results;④Finally based on the static load test of rock-socketed piles in a region inChengdu, finite element model, using load incremental method, find the rock-socketedpile ultimate load,using the method of finite element limit analysis method to solverock-socketed pile ultimate load in engineering practice. Through the study of rock socketed pile model test,found when the pile bearingcapacity is lower than the carrying capacity of the bedrock, the damage occurs in thepile; when the pile bearing capacity is higher than the carrying capacity of the bedrock,the damage occurs on the bottom of the pile and the pile and the surrounding soil be-drock interface; when there are structural surface bedrock, especially weak structuralplane, destruction occurred in the pile surface bedrock and structural weakness.Thesloping bedrock in the face of weak structural ultimate bearing capacity ofrock-socketed piles greater impact,contrast with rock-socketed pile unstructured sur-faces.The bearing capacity of rock-socketed pile unstructured surfaces is four timeshigher than the bearing capacity of rock-socketed pile structured surfaces,when weakstructural plane and the close proximity of rock-socketed piles, bearing capacity ofrock-socketed piles drastically reduced.