客运专线桩复合地基复合模量计算方法探讨

Calculation Method Study on Composite Modulus of Pile Composite Foundation for Passenger Dedicated Line

客运专线对路基沉降控制较普通铁路更为严格,复合模量作为桩复合地基沉降计算的重要参数,是衡量加固区土层刚度与应力扩散作用重要指标,而目前结合面积加权法获取复合模量计算复合地基沉降值与实测值误差较大,探索更为合理桩复合地基的复合模量计算方法已经成为工程界面临重要课题之一。本文采用弹性力学理论法、剪切位移法等,对桩合地基的复合模量进行修正计算,并将成果应用到甬台温客运专线DK273+300搅拌桩联合插塑板(长板-短桩)多元复合地基断面与DK234+600浆喷桩和布袋桩联合处理软基断面沉降计算分析中。研究结果表明:利用修正公式计算复合模量较利用面积比公式计算值大,且不同修正法得到完全不同的计算值,在沉降中要慎重选取计算方法。研究成果可以为客运专线软土桩复合地基设计提供理论参考。

The control of subgrade settlement for passenger dedicated line is much stricter than that of ordinary railway. As an important parameter of settlement calculation of pile composite foundation, composite modulus is an important index to measure the effect of soil stiffness and stress diffusion in reinforced area. However, at present, the error between the settlement value of composite foundation and the measured value is larger than that obtained by using area weighting method. It has become one of the most important topics in the engineering field to explore a more reasonable method for calculating the composite modulus of pile composite foundation. In this paper, the composite modulus of pile composite foundation is modified and calculated by means of elastic mechanics theory, shear displacement method, etc. The results are applied to the DK273 ＋ 300 mixing pile of Ningbo-Taizhou-Wenzhou Railway. In the calculation and analysis of the settlement for soft foundation treated by grouting pile and bag pile at DK234 ＋ 600, the results show that the composite modulus calculated by modified formula is better than that of using the area ratio formula, and larger than the calculated value of the formula, different modified methods are used to obtain completely different calculation values, and the calculation method should be carefully selected in settlement. The research results can provide a theoretical reference for the design of soft soil pile composite foundation of passenger dedicated line.