嵌岩桩模型试验基岩相似材料的配比试验研究

Experimental research on similar material of bedrock proportioning test for rock-socketed pile model test

室内模型试验时,材料的相似模拟对于试验过程和实测数据分析具有重要影响。在前人基岩相似材料研究的基础上,采用正交设计方法,以(重晶石粉+砂)石膏、重晶石粉砂,水石膏等3种组合,每组合设置3个水平,共设计了9组材料配比方案,进行优化匹配,并最终得到能够在嵌岩桩模型试验中性能优良的模型材料配比建议值。试验结果表明:采用普通粉刷石膏作为胶结材料时在满足相似材料密度要求的前提下,材料抗压强度和弹性模量的可变范围较窄,不能满足大部分岩体材料模型试验对相似材料的要求;采用α-高强石膏粉替代普通粉刷石膏粉可以有效提高材料抗压强度和弹性模量,使重晶石粉、砂子、石膏和甘油为原料的相似材料可以较好地模拟出大部分岩体材料基本特性。

The test process and data analysis has a important influence to similar material on the indoor model tests. On the basis of previous research of bedrock similar material, the weight ratio of barite powder plus sand to gypsum powder, the weight ratio of barite powder to sand, the weight ratio of water to gypsum powder are selected as three kinds of combination, and each combination set three levels, a total of nine groups of material proportioning is designed by the orthogonal design method, by optimizing the matching we finally get the recommended value of the excellent performance of the model material ratio which can be used in rock-socketed pile model test. The tests results show that when similar material density meets the requirements, using ordinary plastering gypsum as cementitious materials, the variable range of compressive strength and elastic modulus of the material is small and can＇t meet the needs for rock similar material in different physical model test; using the alpha high-strength gypsum powder instead of the ordinary plastering gypsum powder can improve the material strength and elasticity modulus of the material and it makes the similar material which made by barite powder, sand, plaster and glycerin can simulate most of the basic characteristics of rock materials.