管-土相互作用模型试验的尺寸效应及可靠性分析

Size Effect and Reliability Analysis of the Model Test for Pipe-soil Interaction

为了分析北京地区粉质黏土场地中管-土相互作用土弹簧模型参数,进行了一系列管土相互作用试验。由于人力、经费、场地等原因,模型箱尺寸无法取到无限大,模型箱的尺寸效应有可能使试验数据出现一定偏差。为了检验已开展模型试验结果的可靠性,基于ABAQUS有限元软件进行了数值仿真,探讨了土体的破坏模式,研究了管-土相互作用试验的尺寸效应,并得到如下结论:土体破坏模式可分为深埋和浅埋两种破坏模式;模型箱下方和后方边界对试验结果影响较小,当深径比大于6时,前方边界开始对试验结果产生影响。最后,分析和修正了试验结果并对类似试验中的模型箱尺寸选取给出了建议。

In order to analyze the parameters of soil spring model for the pipeline-soil interaction in the silty clay site in Beijing area, a series of pipe-silty clay interaction tests were carried out and the corresponding experimental results were obtained. Due to limitation of manpower, funding and the site, the size of model box cannot be taken to infinity. The size effect of the model box may lead to some deviation of the test data. To test the reliability of the model test results, the numerical simulation was done on the basis of ABAQUS finite element software, the failure mode of soil was discussed, and a study was conducted on the size effect of the pipe-soil interaction model. Some conclusions are gained as follows ： there are altogether two kinds of soil failure mode deep and shallow failure modes ; the boundary below model box and the rear boundary exercises a minor influence on the test results. The depth diameter ratio exceeding six, the front boundary has a major influence on the experimental results. Finally, the results of experiment are analyzed and corrected, and some suggestions are made on the selection of the model box size in future similar experiments.