人工填土中灌注桩水平静载试验研究

Experimental study on lateral static load test of cast-in-situ pile in artificial filled soil

桩基础的水平承载力受多种因素影响,很难精确计算。《建筑桩基技术规范》(JGJ94-2008)规定:对于受水平荷载较大的设计等级为甲级、乙级的建筑桩基,单桩水平承载力特征值应通过单桩水平静载试验确定。某工程开展结构设计前,对人工填土中的灌注桩进行了低应变桩身完整性测试和水平静载试验,并量测了试验过程中基桩的内力、位移等参数。通过对试验数据的整理、分析得出以下结论:由于人工填土不均匀,试验的水平抗力系数的比例系数离散性较大,属于复杂的地基环境,应做水平静载试验才能获取可靠的水平承载力值;成桩质量对灌注桩水平承载力影响较大,应对水平荷载较大的桩进行桩身完整性试验,确定成桩质量;桩周土水平承载主要影响深度试验值与理论值基本一致。

The horizontal bearing capacity of pile foundation is affected by many factors,and it is difficult to calculate accurately.Technical code for building pile foundation(JGJ 94-2008)stipulates that for building pile foundations with design grades A and B subjected to large horizontal loads,the characteristic value of the horizontal bearing capacity of a single pile shall be determined by the lateral static load test of a single pile.Before the structural design of a project,the low-strain pile integrity test and the lateral static load test of single pile were carried out on the cast-in-situ pile in the artificial fill soil,and the internal force and displacement of the foundation pile during the test were measured.Through the sorting and analysis of the test data,the following conclusions are drawn:Due to the unevenness of the artificial fill soil,the proportional coefficient of the horizontal resistance coefficient has a large discreteness in this test,It belongs to the complex foundation environment,the lateral static load test should be done to obtain a reliable horizontal bearing capacity value;the quality of the pile has a great influence on horizontal bearing capacity of a cast-in-situ pile,the pile integrity test should be carried out on the pile with large horizontal load to determine the pile quality;the experimental value of the main influence depth of soil around the pile is basically consistent with the theoretical value.