多功能CPTU与我国CPT液化判别对比试验研究

Comparative test study on liquefaction discrimination methods of multi-functional CPTU and CPT in China

考虑到孔压静力触探(CPTU)能够同时获取静力触探(CPT)及孔隙水压力测试结果,结合济宁徐州高速公路液化场地CPT和CPTU测试资料,采用我国规范法、通用Robertson法(CPT法)和Juang法(CPTU法)对场地进行了液化评价.利用CPTU土分类图及其状态指标等值线、超孔压、归一化超孔压和新的联合图法对土体空间分布及原位状态进行了分析.结果表明:以规范法为参考时,CPT法、CPTU法分别在预测非液化、液化区域时较为准确,CPTU法在液化区域判别正确率高达96.4%;土分类图能够同时反映土体种类及所处的状态,对其密实状态进行判别,从而有效地进行液化土与非液化土的划分;归一化超孔压法及所提出的新联合图法能够有效评价土体的原位状态,为潜在液化分析提供初判或核验.

Considering that piezocone penetration test(CPTU)can obtain the test results of the cone penetration test(CPT)and the pore water pressure at the same time,combined with the test data of CPT and CPTU of the liquefaction site of Jining-Xuzhou Expressway,the liquefaction evaluation of the site was carried out by the Chinese double-bridge code method,the international Robertson method(CPT method),and the Juang method(CPTU method).The spatial distribution and the in-situ state of the soil were analyzed by the CPTU soil behavior type chart and its state parameter contours,the excess pore water pressure,the normalized excess pore water pressure,and the new union graph method.The results show that when taking the code method as a reference,the CPT method and the CPTU method are accurate in predicting non-liquefied and liquefied cases respectively,and the accuracy of CPTU method in liquefied cases is as high as 96.4%.The soil behavior type chart can simultaneously reflect the type and the state of soils and distinguish the loose or dense state of soils,thus effectively classifying liquefied soils and non-liquefied soils.The normalized excess pore water pressure method and the new union graph method can systematically evaluate the in-situ state of soils,providing a preliminary judgment or verification for the liquefaction evaluation.