岩溶桩基振动台试验中岩体相似材料的配比研究

EXPERIMENT STUDY ON SIMILARITY RATIO OF SIMILAR MATERIAL OF ROCK MASS FOR SHAKING TABLE TEST OF PILE IN KARST REGION

振动台模型试验是现阶段研究地震条件对工程实际影响的有效手段,而选择合适的材料配比是成功模拟原型工程的关键。依托渝黔铁路周家湾大桥,基于分离相似设计方法,采用正交试验以及二次细化试验相结合对模型所需的岩质材料进行配比研究。试验选用重晶石粉、石英砂、铁精粉、石膏以及松香酒精溶液为配比材料,正交试验以岩体密度、重力加速度、几何尺寸为控制指标,通过极差分析法确定各试验材料含量对模型岩体主要参数的影响程度。再利用二次试验进行细化分析,确定最终的材料配合比例。结果表明:(1)各配比材料的比重均会对材料的变形模量、黏聚力及内摩擦角等主要参数造成不同侧重、不同程度的影响。(2)分离相似设计方法可以很好地选择出相似试验中各个部件的主要参数,正交试验和二次细化试验能够快速高效的对主要参数进行设计和测试,最终找出满足模型试验要求的最佳配合比。

Shaking table test is an effective method to study the effect of seismic conditions on engineering practice at present. The selection of appropriate material ratio is the key to successful simulation of the prototype project.Based on Zhoujiawan Bridge of the Chongqing-Guizhou high-speed railway,the orthogonal test is used to study the rock material according to the separation similar design method and secondary refinement test. In this study,barite powder,quartz sand,iron powder,gypsum and rosin alcohol solution are used as proportion materials. The rock mass density,gravity acceleration and geometrical size are regarded as control indexes. By the method of extreme difference analysis,the influence of material contend of model test on simulating the main parameters of rock is studied. Then the second test for refining the analysis and determining the final material mix is conducted. The results show the follows.（ 1） The proportion of materials affects the main parameters such as deformation modulus,cohesion and internal friction angle on different emphasis and different degrees.（ 2） The similarity design method can be used to select the main parameters of each component in the similar test. The orthogonal test and the secondary refinement test can quickly and efficiently design and test the main parameters. Finally the parameters are obtained to meet the requirements of the model test.