中更新世黄土的湿陷特性及其湿陷预测模型  

Collapsible properties of Q_(2)loess and its collapsible prediction model

作　　者：付昱凯[1,2] 李广林 李同录 张子然[1,2] 刘贺 FU Yukai;LI Guanglin;LI Tonglu;ZHANG Ziran;LIU He(School of Geological Engineering and Surveying,Chang’an University,Xi’an,Shaanxi 710054,China;Water Cycle and Geological Environment Observation and Research Station for the Chinese Loess Plateau,Ministry of Education,Zhengning,Gansu 745399,China)

机构地区：[1]长安大学地质工程与测绘学院,陕西西安710054 [2]黄土高原水循环与地质环境教育部野外科学观测研究站,甘肃正宁745399

出　　处：《水文地质工程地质》2025年第1期159-166,共8页Hydrogeology & Engineering Geology

基　　金：陕西省自然科学基础研究计划项目(2022JM-167);国家自然科学基金项目(42474051)。

摘　　要：间歇性的地表灌溉或工程运营引起的长期地表渗漏,会导致深层中更新世(Q_(2))黄土的增湿变形,进而影响构建筑物安全。为了预测Q_(2)黄土的湿陷变形特性,对陕西泾阳原状Q_(2)黄土进行了多个含水率下的高压固结试验,得到不同含水率及压力下的湿陷系数,并基于试验结果,在δ_(s)-lgp半对数坐标系中,利用线性及Lorentz型函数构建Q_(2)黄土湿陷系数的压力相关模型,然后基于模型参数与含水率相关性,建立湿陷系数与压力和含水率的二元函数三维模型。试验结果表明:随着荷载的增大,黄土的湿陷系数在δ_(s)-lgp半对数坐标系中均呈现出线性缓增-骤增-峰值-减小的变化趋势,且各含水率下缓增-骤增阶段的分界压力不随含水率的变化而改变,均为饱和状态压缩曲线的结构屈服压力;各含水率下峰值湿陷系数和对应的压力均随含水率的增大逐渐减小。建立的湿陷系数模型能较好地描述Q_(2)黄土高压力范围内各含水率下湿陷系数随压力的变化,可用来预测Q_(2)黄土在不同含水率和荷载下的湿陷系数,对深厚层Q_(2)黄土的浸水、增湿湿陷评价具有实际意义。Long-term surface leakage caused by intermittent surface irrigation or project operation can lead to the humidification and settlement deformation of deep Q_(2)loess,compromising the safety of the structures.To predict the collapsible deformation properties of Q_(2)loess,a series of high pressure consolidation tests were performed under different water contents on Q_(2)loess from Jingyang of Shaanxi Province.The collapsible coefficients under different water contents were measured by using double-line method tests,and the collapsibility of Q_(2)loess of different water contents and pressures within high pressure range were investigated.Based on these experimental results,a pressure-dependent collapsibility coefficient model in theδs-p semi-logarithmic coordinates was proposed by using linear and Lorentz-type joint functions.Furthermore,a 3D collapsible surface model related to the pressure and water content was proposed based on the correlation analysis between model parameters and water content.The test results indicates that all collapsible coefficients in theδs-p semi-logarithmic coordinates present the trend of linear slow increase-sudden increase-peak-decrease with the increasing pressure.The boundary pressure between the slow increase stage and sudden increase stage remains unaffected by changes in water content and corresponds to the structural yield pressure of the saturated compression curve.Additionally,the peak collapsible coefficient and its corresponding pressure decreases with the increase of water content.The proposed model can accurately describe the variation of collapsibility coefficient of Q_(2)loess with different water contents throughout the high pressure consolidation,which is of practical significance to evaluate the collapsibility of deep and thick Q_(2)loess under water immersion and humidification.

关 键 词：中更新世黄土 湿陷变形 湿陷系数 压力 含水率 湿陷模型 

分 类 号：P642.3[天文地球—工程地质学]