高寒区膨胀土渠道边坡性能演变规律  

Performance evolution of expansive soil canal slope in high cold region

作　　者：蔡正银[1] 朱洵 张晨[1] 黄英豪[1] CAI Zhengyin;ZHU Xun;ZHANG Chen;HUANG Yinghao(Geotechnical Engineering Department,Nanjing Hydraulic Research Institute,Nanjing 210024,China)

机构地区：[1]南京水利科学研究院岩土工程研究所,江苏南京210024

出　　处：《中南大学学报（自然科学版）》2022年第1期21-50,共30页Journal of Central South University:Science and Technology

基　　金：国家重点研发计划项目(2017YFC0405100);国家自然科学基金资助项目(51879166,51709185);中央级公益性科研院所基金基本科研业务费项目(Y320010)。

摘　　要：位于我国西北地区高寒区的供水渠道大多数面对极端寒冷、异常干旱、复杂地质环境等恶劣自然条件,为了防止冻胀往往冬季不供水,渠道每年经历湿干−冻融循环过程。为了研究膨胀土渠道在反复湿干−冻融循环过程中的劣化机理,分别从湿干−冻融循环下膨胀土的裂隙损伤、强度衰减及渠道劣化演变3个方面阐述高寒区膨胀土渠道边坡破坏情况,具体包括:揭示湿干−冻融循环下膨胀土的裂隙空间演化规律,提出基于三维裂隙分布特征的膨胀土裂隙网络结构评价方法及相应的细观结构劣化模型;阐明湿干−冻融循环作用对膨胀土有效抗剪强度指标的影响规律,建立湿干−冻融循环下的渠基土强度衰减方程;研发能够模拟冻融及湿干−冻融循环过程的超重力场大型模拟试验平台,揭示高寒区膨胀土渠道在湿干−冻融反复循环下的长期性能演变规律。该研究成果可为我国高寒区膨胀土渠道工程的设计及长期安全运行提供参考。Most of the water supply channels located in the high cold region of Northwest China are faced with extreme cold,abnormal drought,complex geological environment and other adverse natural conditions.In order to prevent frost heaving,the channels go through the wetting-drying-freezing-thawing cycle every year.In order to study the deterioration mechanism of expansive soil channel during repeated wetting-drying-freezing-thawing cycles,the research results of expansive soil channel slope failure in high cold region were elaborated from three aspects of crack damage,strength attenuation and channel deterioration evolution of expansive soil during wetting-drying-freezing-thawing cycles.The evaluation method of crack network structure of expansive soil based on three-dimensional crack distribution characteristics and the corresponding meso-structure deterioration model were proposed.The influence law of wetting-drying-freezing-thawing cycle on the effective shear strength index of expansive soil was clarified,and the strength attenuation equation of canal foundation soil during wetting-drying-freezing-thawing cycles was established.A large-scale high gravity field simulation test platform was developed to simulate the freezing-thawing and wetting-drying-freezing-thawing cycles,which revealed the long-term performance evolution of expansive soil channel in high cold region during wetting-drying-freezing-thawing cycles.The research results can provide a theoretical basis for the design and long-term safe operation of expansive soil channel engineering in high and cold regions of China.

关 键 词：湿干−冻融循环 膨胀土渠道 裂隙演化 强度衰减 离心模型试验 

分 类 号：TU445[建筑科学—岩土工程]