包裹碎石桩影响范围的模型试验分析

Analysis of Model Test for Influence Scope of Geotextile Encased Gravel Pile

为了研究包裹碎石桩受力时的影响范围,进行了三组不同直径的包裹碎石桩和一组未加固地基的模型试验。通过在承压板之上及其周围土体表面布设百分表,得到了承压板及其周围土体表面的位移;在桩体和桩周围土体内不同深度布置土压力盒,监测了桩体和土体内的应力分布。试验分析结果表明:包裹碎石桩改善了土体的承载力性能,减小了土体表面的位移量,包裹碎石单桩复合地基相比于未加固地基(河沙)的极限承载力约提高了32%;在距离包裹碎石桩中心两倍承压板直径范围之外,基本上没有变形和应力的分布,即包裹碎石桩影响范围的宽度约为四倍承压板直径;包裹碎石桩受力主要影响深度在三倍桩径范围内。

To research on influence scope of geotextile encased gravel pile,the model test of 3 geotextile encased gravel piles with different diameters and 1 unreinforced foundation is carried out. The dial gages are arranged on the bearing plate and around the soil surface to get the displacement of bearing plat and surrounding soil surface. The earth pressure cells are arranged at different depths of soil in and around the pile body to monitor the stress distribution of pile body and soil mass. Test results show that the geotextile encased gravel pile improved the bearing performance of soil and reduced the displacement of soil surface. The ultimate bearing force of composite foundation with geotextile encased gravel pile is increased about 32 % compared with unreinforced foundation（ river sand, the same below）. At the distance two times as much as the diameter of geotextile encased gravel pile,there is no deformation and stress distribution basically. It is said that the influence scope of the geotextile encased gravel pile is about four times as much as the diameter of the footing. And the influence depth of the pile is found to be mainly within three times as much as its diameter.