锚桩法静载试验群桩相互作用解析分析

Analytical Analysis of the Pile Group Interaction in Static Load Tests Using Anchor Pile Method

建立了基于弹性理论法的抗拔单桩解析计算模型,以及考虑试桩与锚桩相互作用的群桩计算模型,利用该计算模型讨论不同地层中抗拔桩桩身变形和内力分布规律,进而分析锚桩法静载试验中地层条件、桩间距等因素对试桩竖向抗压刚度和变形的影响。计算结果表明,桩土刚度比越大,桩-土界面摩阻力和桩身轴力曲线沿深度变化越小,相应桩身上拔位移量越大。土体模量大的地层中桩身轴力衰减最快,浅部土层性质对单桩抗拔承载力起重要作用。试桩、锚桩与地基相互作用可导致锚桩法静载试验中试验桩抗压刚度比真实情况偏大,对静载试验结果修正后能得到与实际情况更为接近的试桩曲线。

Establishes an analytical model for uplift single piles based on the elastic theory method,as well as the pile group calculation model considering the interaction between test pile and anchor piles.Using the calculation model,the deformation and internal force distribution of uplift pile in different strata are discussed,and the influence of factors such as geological conditions and pile spacing on the compressive stiffness and deformation of test piles in static load tests is analyzed.The calculation results indicate that the greater the stiffness ratio of the pile to soil,the smaller the variation of the pile soil interface frictional resistance and pile shaft axial force curve along the depth,and the corresponding pile shaft uplift displacement.The axial force of the pile decreases the fastest in layers with high soil modulus,and the properties of the shallow soil layer play an important role in the uplift bearing capacity of single pile.The interaction between the test pile,anchor piles,and soil can lead to a higher compressive stiffness of the test pile in the static load test compared to the actual situation.After correcting the static load test results,the Q-s curve of test pile that is closer to the actual situation can be obtained.