水泥砂浆桩复合地基力学性状的数值分析

:基于有限差分数值方法，考虑地基材料的非线性特性，通过模拟复合地基桩土应力比、复合模 量随荷载、桩长、置换率和褥垫层的变化情况，分析了水泥砂浆桩复合地基桩土作用机理、桩土荷载分担 规律及其变形特性。结果表明:桩体置换率增加，桩土应力比逐渐减小，复合模量逐渐增加，置换率超过 ２０％，桩土应力比变化很小，并趋于稳定。置换率超过２５％，置换率对复合模量的影响较小；桩长增加， 桩土应力比增大，复合模量增加，桩长超过１４ｍ，桩土应力比增长缓慢，复合模量亦趋于稳定；桩土应力 比随着褥垫层厚度的增大而减小，随着褥垫层模量的增加而增大，宜设置褥垫层厚度１００ｍｍ～３００ｍｍ， 褥垫层模量３０ＭＰａ～６０ＭＰａ。

Numerical Analysis for Mechanical Properties of Composite Foundation of Cement Mortar Pile

Taking the material＇ s nonlinear characteristics into consideration and based on the numerical method of finite difference, the soil-pile interaction mechanism, the soil-pile load sharing law and the deformation characteristics in the composite foundation of cement mortar pile are studied through analyzing the pile-soil stress ratio under different pile lengths, replacement ratios and cushion conditions. The results show that： With the increase of replacement ratio, the pile-soil stress ratio decreases and the composite modulus increases gradually; as the replacement ratio exceeds 20%, the pile-soil stress ratio has no significant change and tends to be stable. As the ratio exceeds 25%, the influence of replace- ment ratio on the composite modulus reduces sharply. The pile-soil stress ratio and composite modulus increase with the pile length increasing; as the pile length exceeds 14 m, the pile-soil stress ratio grows slowly, and the composite modulus tends to be stable. The pile-soil stress ratio decreases with the cushion thickness increasing, and increases with its modu- lus increasing; the cushion thickness should be set for 100 rnm - 300 mm and the cushion modulus＇ s appropriate range is 30 MPa- 60 MPa.