基于多功能CPTu与CPT锥尖阻力的土体参数对比分析

Comparative Analysis of Soil Parameters Based on Multifunctional CPTu and CPT Cone-Tip Resistance

(孔压)静力触探(CPTu/CPT)是取得易扰动土体参数的原位测试方法之一,其测试结果受探头尺寸的影响.采用多功能CPTu与传统CPT在开封一场地同时进行测试,对所测锥尖阻力(q_(t)/q_(c))进行比较分析,得到了不同方法所测q_(t)/q_(c)的相关关系.同时,采用地震波CPTu对场地波速(V_(s))进行测试,建立了q_(t)/q_(c)与V_(s)的关系.结合q_(t)/q_(c)与压缩模量(E_(s))、最大剪切模量(G_(max))的经验系数,分析了q_(t)/q_(c)与不同参数的相关关系.结果表明:q_(t)与q_(c)近似1∶1,两者相对误差集中于-0.15~+0.15范围内;q_(t)/q_(c)与Vs均存在良好的幂函数相关关系,但q_(t)拟合度更高;q_(t)与Gmax成幂函数相关关系,q_(t)/q_(c)与E_(s)成线性相关关系,q_(t)计算结果与室内实验结果更接近.因此,可通过CPTu测试估算土体参数,为取得易扰动土体参数提供了新选择.

CPTu/CPT is one of the in-situ test methods to obtain the parameters of easily disturbed soil,The test results are affected by the probe size.Multifunctional CPTu and traditional CPT were used to test at the same site in Kaifeng,and the correlation of tip resistance q_(t)/q_(c)measured by different methods was obtained.The seismic wave CPTu was used to test the site wave velocity(V_(s))at the same time,and the correlation of tip resistance q_(t)/q_(c)and V_(s) was built.Combined with the empirical coefficients of q_(t)/q_(c),compression modulus(E_(s))and maximum shear modulus(G_(max)),the correlation between q_(t)/q_(c)and different parameters was analyzed.The results show that q_(t)and q_(c)are approximately 1∶1,whit the relative error between them concentrated in-0.15-+0.15,and q_(t)/q_(c)has a good power function correlation with Vs,but q_(t)has higher fit;the relationship between q_(t)and Gmax is power function,and q_(t)/q_(c)has linear correlation with E_(s).The results of q_(t)calculation are closer to those of laboratory experiments.Therefore,soil parameters can be estimated by CPTu test,which provides a new choice for obtaining easily disturbed soil parameters.