摘要
在强渗流砂土地层中,常规的地层注浆法难以达到理想的加固、封水效果。为了研究富水砂土地层冻结-注浆联合体的力学特性,通过三轴试验对人工冻结水泥砂土的应力应变关系及其影响因素开展研究,探讨不同冻结环境温度、养护龄期和围压等条件下试样应力应变关系变化规律及强度机理。结果表明:冻结水泥砂土应力应变曲线具有一定应变强化的非线性延性阶段,整体包括密实阶段,线弹性阶段,非线性延性阶段,破坏阶段,呈应变软化型。冻结环境温度的降低、养护龄期的增加使得土体黏聚力和内摩擦角呈非线性增长趋势,提高了冻结水泥砂土抗剪强度,减少了非线性延性阶段应变占比,增强了冻结水泥砂土的脆性;围压的增大提高了冻结水泥砂土抗剪强度,增加了非线性延性阶段应变占比,提高了冻结水泥砂土的延性。基于莫尔-库伦强度准则,建立考虑冻结环境温度和养护龄期综合影响的冻结水泥砂土强度非线性预测模型,预测结果与实测值误差小于5%。研究成果可为富水砂土地层冻结-注浆联合加固方案精细化设计提供参数支持。
Reinforcement and water sealing effect difficult to achieve by conventional stratum grouting method in strong seepage sandy soil stratum.In order to study the mechanical characteristics of freezing-grouting combination in water-rich sand stratum,the stress-strain relationship and its influencing factors of artificially frozen cement sand were studied by triaxial tests,and the variation law and strength mechanism of stress-strain relationship of samples under different freezing temperature,curing age and confining pressure were discussed.The results show that the stress-strain curve of frozen cement-sand has a certain strain-hardened nonlinear ductility stage including compaction stage linear elasticity stage nonlinear ductility stage and strain-hardening stage.The non-linear increase of cohesion and internal angle of frozen cement-sand due to the curing age of freezing temperature increases the shear strength of frozen cement-sand,and the non-linear ductility phase strain ratio enhances the brittleness of frozen cement-sand.The increase of confining pressure increases the shear strength of frozen cement-sand,and the proportion of strain in nonlinear ductility stage improves the ductility of frozen cement-sand.Based on Mohr-Coulomb strength criterion,a non-linear strength prediction model of frozen cement sand was established,which considered the influence of freezing temperature and curing age.The error between the predicted results and the measured values is less than 5%The research results can provide parameter support for the fine design of freezing-grouting combined reinforcement scheme for water-rich sandy soil stratum.
作者
袁昌
钟天乾
马起涛
陈鑫
李栋伟
赖远明
YUAN Chang;ZHONG Tian-qian;MA Qi-tao;CHEN Xin;LI Dong-wei;LAI Yuan-ming(School of Civil and Architectural Engineering,Donghua University of Technology,Nanchang 330013,China;Jiangxi Geological Environment and Underground Space Engineering Research Center,Nanchang 330013,China;State Key Laboratory of Frozen soil Engineering of Northwest Institute of Ecological Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;School of Architectural Engineering,Dalian University,Dalian 116622,China;School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China)
出处
《科学技术与工程》
北大核心
2025年第8期3359-3371,共13页
Science Technology and Engineering
基金
国家自然科学基金(42107203,42061011,41977236)
冻土工程国家重点实验室开放基金(SKLFSE202012)
江西省自然科学基金(2023BAB214077
2022BBG71W01
20232BBE50025)
东华理工大学自然科学基金(DHBK2019251)。
关键词
冻土工程
应力-应变
冻结水泥砂土
抗剪强度
frozen soil engineering
stress-strain
frozen cement-sand soil
shear strength
