粉喷桩复合地基桩土应力比的原型测试分析

Analysing the Prototyping Measurements of Pile-Soil Stress Ratio on the Composite Ground with Dry-Cement Jet Mixing Piles

通过对泉州市安吉路软基试验段实测 ,探讨粉喷桩复合地基的桩土应力比n和地基沉降的变化规律 .结果表明 ,n值随荷载增大而增大 ,但又随沉降增大而减小 ,而且工程实测的n值略显偏小 .导致n值较小的主要原因是 ,复合地基变形较大和上部桩间土为模量较大的填砂 ,桩、砂的变形模量接近 .鉴于前述原因 ,重要工程中利用实测桩土应力比计算复合地基沉降合理 .

In a test sector of soft ground on Anji Road of Quanzhou, the field measurements of pile-soil stress ratio and subsidence of foundations are performed on the composite ground with dry-cement jet mixing piles. The author inquires into the regular pattern of the change of n by way of these field measurements. As shown by the test, value n increases with the increase of load but it decreases with the increase of subsidence. The measured value n of this project is to the small side. The principal causes of a fairly small value n include: a fairly great deformation of foundation; the interpile soil on the upper part are sand filling with fairly great modulus; pile and sand have approximate modulus of deformation. In view of causes mentioned above, it is reasonable for the important projects to calculate subsidence of composite ground by using measured pile-soil stress ratio.