摘要
地震过程中地下结构变形受周边土层变形制约,为揭示土–地下结构间复杂的相互作用,在自行研制的岩土综合试验模型箱内,针对砂土场地中单层箱型地下结构,开展了以土体变形为控制变量的大型推覆试验。模型箱内推覆板按照倒三角形分布位移模式进行水平推覆,即推覆板绕底部转动,转角由0逐级递增至1/60,重点对比了地下结构及其周围土体在推覆作用下的反应特性。试验结果表明:转角为1/120时,推覆端内侧壁中间偏上6 cm处产生水平贯通裂缝,转角为1/150时,被动端内侧壁中间偏下11 cm处产生水平贯通裂缝,地下结构受到挤压变形和剪切变形的耦合作用;结构推覆端侧壁顶底水平相对位移明显小于辅助观测面内等代土体,侧壁破坏后结构与土体变形的比值由0.44增至0.75,同时土体和结构所受倒三角形水平荷载的比值由试验初期的0.24下降至0.10并趋于稳定,结构破坏后又上升至0.32,土–结构相互作用程度会随着土和结构状态变化而改变;土体水平基床系数随加载水平增大而减小,且始终在规范给定的范围内变化,而结构因失效破坏和角部应力集中等原因,侧壁水平基床系数波动范围较大。
The deformation of underground structures is restricted by that of the surrounding soil during earthquake. In order to reveal the complex interaction between the soil and the underground structures, based on the self-developed geotechnical comprehensive test model box, a large-scale pushover test on soil–underground structures is carried out with soil deformation as the control variable aiming at a single-story box type underground structure in sandy soil. The pushing plate in the model box is pushed horizontally according to the inverted triangle distribution displacement mode, namely the pushing plate is rotated around the bottom, and the rotation angle increases step by step from 0 to 1/60. The response characteristics of the underground structures and the surrounding soil under pushover action are mainly compared. The test results show that a horizontal penetration crack occurs at 6 cm above the middle of the inner wall in the pushing end when the rotation angle reaches 1/120,and a horizontal penetration crack occurs at 11 cm below the middle of the inner wall in the passive end when it reaches 1/150.The underground structures are subjected to the coupled action of extrusion deformation and shear deformation. The horizontal relative displacement between top and bottom of the side wall in the pushing end is significantly smaller than that of the soil at the corresponding position in auxiliary observation plane, and the deformation ratio of the structures to the soil increases from 0.44 to 0.75 after failure of the side wall. Meanwhile, the ratio of inverted triangle horizontal load between the soil and the structures decreases from 0.24 in the initial stage of the test to 0.10 and keeps stable, then increases to 0.32 after failure of the structures, and the degree of soil–structure interaction varies with the state change of the soil and structures. The horizontal coefficient of subgrade reaction in the soil decreases with the increase of loading level, and always changes within the given range of code. However, the horizontal coefficient of subgrade reaction on side wall fluctuates widely due to the failure of the structure and stress concentration at the corner.
作者
景立平
徐琨鹏
程新俊
梁海安
宾佳
JING Li-ping;XU Kun-peng;CHENG Xin-jun;LIANG Hai-an;BIN Jia(Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China;Institute of Disaster Prevention,Langfang 065201,China;School of Civil and Architectural Engineering,East China University of Technology,Nanchang 330013,China;College of Civil Engineering,Hunan University of Technology,Zhuzhou 412000,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2022年第9期1567-1576,共10页
Chinese Journal of Geotechnical Engineering
基金
中国地震局工程力学研究所基本科研业务费专项项目(2017B10)
国家重点研发计划项目(2016YFC0800205)
国家自然科学基金项目(52008081)。
关键词
地下结构
抗震性能
推覆试验
土–结构相互作用
基床系数
underground structure
seismic performance
pushover test
soil–structure interaction
coefficient of subgrade reaction
