黄土沟壑区高填方地基工后沉降控制因素敏感性分析  

Sensitivity analysis of control factors on post construction settlement of high fill embankment in loess gully region

作　　者：马云峰 田永辉 刘安龙 逯金文 朱才辉[2,3] MA Yunfeng;TIAN Yonghui;LIU Anlong;LU Jinwen;ZHU Caihui(China Jikan Research Institute of Engineering Investigations and Design,Co.,Ltd.,Xi'an 710043,China;Institute of Geotechnical Engineering,Xi'an University of Technology,Xi'an 710048,China;Shaanxi Engineering Technology Research Center for Urban Geology and Underground Space,Xi'an 710068,China)

机构地区：[1]机械工业勘察设计研究院有限公司,陕西西安710043 [2]西安理工大学岩土工程研究所,陕西西安710048 [3]陕西省城市地质与地下空间工程技术研究中心,陕西西安710068

出　　处：《长沙理工大学学报（自然科学版）》2023年第3期79-90,共12页Journal of Changsha University of Science and Technology:Natural Science

基　　金：国家自然科学基金资助项目(52279110);陕西省重点研发计划项目(2022SF-197、2021SF2-02);陕西省城市地质与地下空间工程技术研究中心开放性课题(2022KT-01)。

摘　　要：【目的】研究不同控制因素对黄土沟壑区高填方地基工后沉降的敏感性,为高填方工程的设计施工提供科学依据。【方法】通过室内试验研究第四纪晚更新世(Q3)黄土的修正剑桥模型参数随竖向荷载、含水率、压实度的变化规律,并采用PLAXIS数值分析方法对影响高填方地基工后沉降的因素的敏感性进行对比分析。【结果】Q_(3)黄土的修正压缩指数、修正回弹系数和修正蠕变指数均随竖向荷载和含水率的增大呈先增大后减小的趋势,随压实度的增大呈线性增长趋势;填料的含水率、压实度与填方高度对高填方地基的工后沉降影响较大,沟谷底部宽度、坡度、原地基厚度、填土速率、桩长、桩间距及桩径等因素对其影响较小。【结论】黄土沟壑区高填方工程应尽量降低填方设计高度,控制填料含水率,使其接近最优含水率,且宜选在黄土层厚度不大、沟谷坡度大于75°、沟谷底部宽度小于100 m的区域。[Purposes]To provide the scientific basis of suitable control scheme for high fill engineering design,the sensitivity of different control factors for post-construction settlement of high fill foundation in loess gully region were studied by this paper.[Methods]The modified Cambridge model parameters of Quaternary Late Pleistocene(Q_(3))loess under different vertical loads,water content and compactness are studied by laboratory experiments.The sensitivity of the factors affecting the post-construction settlement of high fill foundation is compared and analyzed by the numerical software PLAXIS.[Findings]The modified compression index,modified rebound coefficient and modified creep index of the Quaternary Late Pleistocene(Q_(3))loess firstly increase and then decrease with the vertical load and water content,and linearly increase with the compaction degree.The water content,compaction degree and fill height of the filler have significant influence on the postconstruction settlement of high-fill foundation,while the width of the bottom of the gully,slope,thickness of the original foundation,fill rate,pile length,pile spacing and pile diameter have little influence on it.[Conclusions]The design height of high fill projects in loess gully region should be reduced as far as possible,and the water content of fill should be controlled to make it close to the optimal water content.Furthermore,location of fill should be selected in the region with little loess thickness,gully slope greater than 75°and gully bottom width less than 100 m.

关 键 词：黄土沟壑区 高填方地基 工后沉降 敏感性分析 控制因素 Q3黄土 

分 类 号：TU444[建筑科学—岩土工程]