干湿循环下EICP联合黄原胶加固钙质粉土劣化特性试验研究  

Experimental study on degradation of EICP and xanthan gum treated calcareous silt under wetting-drying cycles

作　　者：付贵永 肖杨[1,2,3] 史金权 周航 刘汉龙[1,2,3] FU Guiyong;XIAO Yang;SHI Jinquan;ZHOU Hang;LIU Hanlong(School of Civil Engineering,Chongqing University,Chongqing 400045,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area,Chongqing University,Chongqing 400045,China;National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas,Chongqing 400045,China)

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]重庆大学山地城镇建设与新技术教育部重点实验室,重庆400045 [3]库区环境地质灾害防治国家地方联合工程研究中心,重庆400045

出　　处：《岩土工程学报》2024年第11期2341-2351,共11页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金青年基金项目(52108301);重庆市杰出青年科学基金项目(cstc2021jcyj-jqX0017);重庆市留学生创新支持计划(cx2021048)。

摘　　要：生物聚合物(BP)是近年来一种新兴的环境友好型土体加固生物材料,然而因其具有水溶性,BP固化土在循环浸水工况下强度逐渐劣化。因此,提高BP加固土的耐侵水性十分重要。通过植物脲酶诱导碳酸钙沉(EICP)联合黄原胶(XG)对南海钙质粉土进行加固,对不同干湿循环次数下的固化粉土进行一系列物理,力学和微观分析测试。研究结果表明:随着黄原胶含量和EICP反应液浓度的增加,黄原胶(XG)固化土和联合(XG-EICP)固化土的无侧限抗压强度提升显著;随着干湿循环次数的增加,黄原胶固化土的强度降幅大于联合固化土,联合固化土具有更优的抗干湿循环特性。EICP和XG-EICP溶液试验结果表明:XG在EICP溶液中可以生成不溶于水的凝胶状沉淀,且粘连在XG-EICP沉淀上的碳酸钙颗粒较其纯EICP生成得碳酸钙颗粒体积更大。试验验证了植物脲酶诱导碳酸钙沉淀提高生物聚合物固化土抗干湿循环侵蚀的可行性,有望为海洋土加固提供新的思路与方法。The biopolymer(BP)has been an emerging environment-friendly biomaterial for soil reinforcement in recent years.However,due to its water solubility,the strength of the BP-stabilized soil gradually deteriorates under cyclic wetting-drying conditions.Therefore,it is very important to improve the water resistance of the BP-strengthened soil.In this study,the calcareous silt in the South China Sea was reinforced by the plant urease-induced calcium carbonate precipitation(EICP)combined with the xanthan gum(XG).A series of physical,mechanical and microscopic tests are carried out on the samples under different wetting-drying cycles.The test results show that with the increase of the XG content and plant urease concentration,the unconfined compressive strength of the XG-stabilized soil and XG-EICP-stabilized soil increases significantly.With the increase of the wetting-drying cycles,the strength decrease of XG-stabilized soil is greater than that of the joint-stabilized soil,and the joint-stabilized soil has better resistance to the wetting-drying cycles.The results of the EICP and XG-EICP solution tests show that the XG can form a water-insoluble gel-like precipitate in the EICP solution,and the calcium carbonate particles attached to the XG-EICP precipitate are larger than those produced by the pure EICP.The tests verify the feasibility of the EICP to improve the erosion resistance of the biopolymer-solidified soils against the wetting-drying cycles,and it is expected to provide new ideas and methods for marine soil reinforcement.

关 键 词：黄原胶 EICP 无侧限抗压强度 剪切波速 干湿循环 

分 类 号：TU432[建筑科学—岩土工程]