预固结对长江漫滩相软土抗剪强度的影响研究  

Influence of Preconsolidation on the Shear Strength of the Soft Soil in Floodplain Facies of Yangtze River

作　　者：崔志鹏 严刚[1,2] 王军 钟萍 王振祥 吴琪 Cui Zhipeng;Yan Gang;Wang Jun;Zhong Ping;Wang Zhenxiang;Wu Qi(The 1st Geological Brigade of Jiangsu Geology and Mineral Exploration Bureau,Nanjing 210041,Jiangsu,China;Total Factor Testing Laboratory of Engineering Technology Innovation Center of Urban Underground Space Exploration and Evaluation,Ministry of Natural Resources,Nanjing 210041,Jiangsu,China;Institute of Geotechnical Engineering,Nanjing Tech University,Nanjing 210009,Jiangsu,China)

机构地区：[1]江苏省地质矿产局第一地质大队,江苏南京210041 [2]自然资源部城市地下空间探测评价工程技术创新中心,全要素测试实验室,江苏南京210041 [3]南京工业大学岩土工程研究所,江苏南京210009

出　　处：《岩土工程技术》2024年第1期116-120,共5页Geotechnical Engineering Technique

基　　金：江苏省地质学会重点学术研究课题和学术交流方向资助项目“地铁动载作用下长江漫滩相软土沉降机理研究”(JSDZXH-P2023-07);中国博士后科学基金项目“饱和粗细粒混合料动力特性及地震液化评价方法研究”(2021M690279)。

摘　　要：固结快剪试验是获取软土固结不排水抗剪强度的重要方法,长江漫滩相软土具有压缩性高、孔隙比大、含水率高、渗透率低、固结时间长等特点,严重影响了软土固结快剪试验的生产效率。为研究预固结对长江漫滩相软土抗剪强度的影响,并探索提高漫滩相软土固结快剪试验效率的方法,以南京长江漫滩相软土为研究对象,制定了预固结-卸载剪切、正常固结剪切、预固结-卸载-再固结剪切3种试验方案,开展了一系列固结和剪切试验。试验研究表明:长江漫滩相软土是一种前期固结迅速,后期固结稳定缓慢的软土;固结25 min时固结度可以达到95%,而完全固结稳定需要5~8 h;软土抗剪强度均随固结度U的增加呈增大趋势,其增长速度逐渐减缓,各荷载条件下抗剪强度随U提高的增长幅度基本相同;当固结度为70%~80%时,其抗剪强度达到完全固结时的90%~95%。研究成果可为软土固结快剪试验的方法改进提供参考。The consolidation fast shear test is an important method to obtain the consolidation and undrained shear strength of soft soil,and the soft soil of the Yangtze floodplain has the characteristics of high compressibility,large pore ratio,high moisture content,low permeability,and long consolidation time,which seriously affects the production efficiency of soft soil consolidation fast shear test.To study the effect of preconsolidation on the shear strength of the Yangtze River floodplain facies soft soil and explore the method to improve the efficiency of fast shear tests for consolidation of floodplain soft soil,a series of consolidation and shear tests were carried out,taking the Nanjing Yangtze River floodplain soft soil as the research object.The results show that the Yangtze River floodplain facies soft soil is a kind of soft soil with rapid consolidation in the early stage and stable and slow consolidation in the later stage.The consolidation degree can reach 95%when consolidating for 25 minutes,while it takes 5~8 hours to fully consolidate and stabilize.The shear strength of soft soil increased with the increase of consolidation degree U,and its growth rate gradually slowed down.The increase of shear strength with the increase of U under each load condition was basically the same.When the degree of consolidation is 70%~80%,its shear strength reaches 90%~95%of that when fully consolidated.This study can provide a reference for improving the fast shear test method of soft soil consolidation.

关 键 词：漫滩相软土 预固结 固结度 固结时间 抗剪强度 

分 类 号：TU411[建筑科学—岩土工程]