预置孔联合旁压试验的水泥搅拌桩强度检测方法研究  

Test Method of Cement-mixing Pile Strength by Pre-set Hole Combined with Pressuremeter Test

作　　者：王少华 王伟[2] 侯宇宙 李国维[2] 贺冠军[2] 周洋[3] WANG Shao-hua;WANG Wei;HOUYu-zhou;LIGuo-wei;HE Guan-jun;ZHOU Yang(Zhongshan-Jiangmen Expressway Reconstruction Management Department of Guangdong Road&Bridge Construction Development Co.Ltd,Guangzhou 510510,China;Key Laboratory of Geomechanics and Embankment Engineering of Ministry of Education,Hohai University,Nanjing 210098,China;Civil Engineering School,Henan University of Technology,Zhengzhou 450001,China)

机构地区：[1]广东省路桥建设发展有限公司中江高速公路改扩建管理处,广州市510510 [2]河海大学岩土力学与堤坝工程教育部重点实验室,南京市210098 [3]河南工业大学,郑州市450001

出　　处：《公路》2024年第10期62-68,共7页Highway

基　　金：国家自然科学基金项目,项目编号51908235,42177126。

摘　　要：提出利用预置孔联合旁压试验对水泥搅拌桩强度进行检测的方法,通过现场原位旁压试验曲线,探究水泥搅拌桩的临塑压力、极限压力、旁压模量和变形模量随深度的变化规律。基于旁压试验结果和H-B强度准则对水泥搅拌桩体抗压强度进行预测,并与抽芯取样的无侧限抗压强度结果进行比较分析。研究发现在水泥搅拌桩预置孔进行的旁压试验可以得到具有典型的3个阶段特征,即恢复阶段、似弹性阶段、塑性扩展阶段的S~P曲线。临塑压力和极限压力在浅部位置处最大,随着位置深度增加临塑压力逐渐减小,通过极限压力可估算临塑压力。变形模量与旁压模量的分布规律整体上与特征压力分布规律一致,变形模量与旁压模量的比值在2左右。就文中案例而言,当表征水泥搅拌桩的桩身破碎程度参数s取0.7时,理论计算值和试验值吻合度较好。A method of pre-set hole(PSH)combined with pressuremeter test(PMT)to testing the strength of cement-mixing pile is proposed in the study.Based on the in-situ side pressure test curve,the variation law of the temporary plastic pressure,ultimate pressure,side pressure modulus and deformation modulus of cement mixing pile with depth are explored.Based on the PMT results and the H-B strength criterion,the unconfined compressive strength is calculated and compared with the laboratory result using the core drilling samples.From this research,it is found that the resulted S~P results from PMT in the pre-set hole for cement-mixing pile followed a typical 3-stage features,namely recovery stage,quasi-elastic stage and plastic expansion stage.The critical pressure and limit pressure have the maximum values at the top and gradually decreases with depth,and the limit pressure can be evaluated as 2 times of critical pressure.The distribution for modulus of pressuremeter and modulus of deformation with depth are similar to the critical pressure and limit pressure,and the ratio of modulus to modulus of deformation is around 2.With consideration of this study only,the breakage index can be used as s=0.7,and with this value the analytical solution could predict the unconfined compressive strength very well.

关 键 词：水泥搅拌桩 现场试验 临塑压力 旁压模量 强度准则 抗压强度 

分 类 号：U416.1[交通运输工程—道路与铁道工程] TU472.36[建筑科学—结构工程]