The Study On Effect Of Aspect Ratio And Rock-socketed Ratio Of Socketed Pile Of Cast-in-drilled-hole To It's Bearing Capacity

Rock Socketed pile foundation has been widely used in high-rise buildings and bridges and other large projects.But,considering the diversity of soil properties around the pile and the diversity of rock mass characteristics around the pile,and the complexity of the Interaction between the soil around pile and pile and the complexity of the Interaction between the rock around pile and pile,and the test pile needs to consume a lot of material and site in situ test pile test is not accurate and so on.These factors have led to the results of the pile site in situ test difficult to achieve accurate,it is difficult to achieve consistent with the actual.Therefore,the current domestic norms on the ultimate bearing capacity of the semi-theoretical semi-empirical formula will be more or less with the actual project there is a lot of inconsistencies.Therefore,it is very important to carry out more in-depth and more thorough research on the ultimate bearing capacity of rock-socketed piles.This article,through the collection and finishing 180 test pile information,typical 38 test piles(Included 30 soft rock socketed piles and 8 hard rock socketed piles)are selected from the above pile as the test pile data for the calculation of ultimate bearing capacity of rock-socketed piles.The most direct and effective test method of ultimate bearing capacity of rock-socketed piles is undoubtedly the most in situ test.The in situ test data of 38rock-socketed piles will be used to analyze and calculate,and the finite element numerical simulation is used to check and compare the research.Therefore,the modified formula of considering the effect of aspect ratio and rock-socket ratio on the ultimate bearing capacity of rock-socketed piles is deduced.The main contents of this paper are as follows:(1)Through careful study of the development process of rock-socketed piles at home and abroad,the loading mechanism and load transfer characteristics of rock-socketed piles are summarized and summarized.Analysis of vertical bearing capacity of rock-socketed piles and analysis of pile-soil side resistance,pile-rock side resistance and rock-socketed pile end resistance of rock-socketed pile,find the main factors influencing the vertical ultimate bearing capacity of rock-socketed piles: The nature of the soil around the rock-socketed pile,the nature of rock layers around rock-socketed piles,relative displacement between pile and soil around pile,relative displacement between pile and pile side rock body,relative displacement between pile and pile end rock,aspect ratio and rock-socket ratio of rock-socketed piles,whether the hole cleaning is complete and other factors.(2)This article analyzes the calculation formulas of the ultimate bearing capacity of rock-socketed piles in the specification,and analyzes the characteristics and shortcomings of the formulas.(3)The pile test data collected in this paper are collected and analyzed.Analysis and summary the aspect ratio of rock-socketed piles,rock-socket ratio of rock-socketed piles,soil side resistance share load ratio,rock mass side resistance sharing load ratio,pile end resistance sharing load ratio and other.And then the theoretical analysis and data processing,by using the curve fitting method of mathematical statistics and derive the soil side resistance coefficient of soil in soft rock rock-socketed pile and hard rock rock-socketed pile,the lateral resistance coefficient,the end resistance coefficient.Combine with the calculation formula of the ultimate bearing capacity of rock-socketed piles with the existing highway bridge gauge,the formula of ultimate bearing capacity of rock-socketed pile after correction is obtained.(4)For this article,the revised formula.The data of the actual engineering case data are respectively substituted into the existing highway bridge and the empirical formula and as well as the correction calculation formula of the ultimate bearing capacity of rock-socketed piles in this article.Calculate the corresponding results and comparative analysis,this article validates the rationality and feasibility of the calculation formula of ultimate bearing capacity of rock-socketed piles.