摘要
冻融循环引起的井壁剥落是坎儿井破坏的初始阶段和主要形式。为探究高模数硅酸钾(PS)加固井壁的工程特性,进行了PS改良坎儿井黄土冻融循环后的冻胀与强度试验。结果表明:掺入PS可显著提高土样的起始冻胀含水率,并大幅削弱土体冻胀量,但冻胀量并不随PS掺量的增加而降低,掺量过大使孔隙水分存在部位发生变化是其主要原因。随着PS掺量的增加,剪应力-剪切位移曲线由硬化向软化过渡的同时,屈服前曲线呈现上凸-近似线性-下凸的过渡特征,说明土体逐渐由摩擦型向凝聚型材料转变。随着PS掺量的增大,土样峰值强度显著提高,其中黏聚力大幅度增大,因PS胶体包裹性增强,内摩擦角随PS掺量的增加而有所衰减。3%PS掺量在抑制井壁冻胀、加固坎儿井方面是可行的。研究结果对PS加固坎儿井井壁具有一定的理论与实际指导意义。
Sidewall spalling caused by freeze-thaw cycles is the initial stage and main form of Karez failure.In order to explore the engineering characteristics of high modulus potassium silicate(PS)reinforced sidewall,frost heave and strength tests of PS modified Karez loess after freeze-thaw cycles were carried out.The results show that PS can significantly increase the initial frost heaving water content,and greatly reduce the frost heaving amount of the soil samples,but the frost heaving amount does not decrease with the increase of PS content,mainly because the location of pore water changes with the increase of PS content.With the increase of PS content,the shear stress-strain curve transits from hardening to softening.At the same time,the curve before yield presents the transition characteristics of upward convex to approximate linear to downward convex,which indicates that the soil texture gradually changes from friction type to solidified type.With the increase of PS content,the peak strength of the samples increases significantly,among which the cohesion increases greatly,because the internal friction angle decreases with the increase of PS content.3%PS content is feasible in restraining frost heave and strengthening sidewall for Karez.The research results have certain theoretical and practical significance for the reinforcement of Karez sidewall.
作者
安鹏
朱石磊
强城成
王松鹤
徐强
AN Peng;ZHU Shilei;QIANG Chengcheng;WANG Songhe;XU Qiang(School of Geological Engineering and Geomatics,Chang’an University,Xi’an 710054,China;Institute of Geotechnical Engineering,Xi’an University of Technology,Xi’an 710048,China)
出处
《水资源与水工程学报》
CSCD
北大核心
2022年第1期171-177,共7页
Journal of Water Resources and Water Engineering
基金
国家自然科学基金项目(41807243、51778528)
中央高校基本科研业务费项目(300102269102)
安康市科学技术研究发展计划项目(AK2019SF-03)。
关键词
坎儿井
黄土
高模数硅酸钾
抗冻胀性
强度特性
Karez
loess
high modulus potassium silicate(PS)
anti-frost heave
strength characteristics
