摘要
针对于实际工程中大量存在的挡土墙、基坑等平面应变问题,依据Mohr-Coulomb、SMP、3√σ空间滑动面、LadeDuncan、AC-SMP和广义Mises强度准则所建立的平面应变条件下的中主应力公式,推导出了基于各强度准则的主、被动土压力计算公式,将其推广至黏性土,对平面应变条件下的主、被动土压力进行了计算与分析,并与实测土压力数据进行了对比分析。研究结果表明,土破坏时中主应力的发挥程度对土压力的大小影响显著;Mohr-Coulomb强度准则未考虑中主应力效应,计算的主动土压力偏大,被动土压力偏小,在设计上趋于保守;SMP强度准则、Lade-Duncan强度准则、3√σ空间滑动面强度准则、AC-SMP强度准则的计算结果更接近实测土压力,其中AC-SMP强度准则的计算结果最为准确;广义Mises强度准则的土压力计算结果不再适宜于描述挡墙上土压力的大小。在进行平面应变问题的挡土结构工程设计时,可选择相适应的土压力计算公式,考虑平面应变条件下中主应力对土强度的贡献,充分发挥土的强度潜能,在工程建设中提高经济效益。
A great number of problems in practical projects like retaining walls and foundation pits are under plane strain state.According to the formulas for the intermediate principal stress under the plane strain established by Mohr-Coulomb,SMP,3√σspatially mobilized plane,Lade-Duncan,AC-SMP strength criterion and generalized Mises criterion,the formulas for the active earth pressure and passive earth pressure are derived in these strength criterions and extended to clay,the calculated active and passive earth pressures are compared with the measured data.The results indicate that the development degree of the intermediate principal stress has a significant impact on the earth pressure in the process of soil break.The calculated active earth pressure in the Mohr-Coulomb strength criterion is larger and the passive earth pressure is smaller than the practical one because the effect of the intermediate principal stress is not considered,and the design tends to be conservative.The calculated results by the criteria of SMP,3√σspatially mobilized plane,Lade-Duncan and the AC-SMP strength are close to the measured data,among which the results by the AC-SMP strength criterion is much closer.The earth pressure calculated by the generalized Mises criterion is no longer appropriate to describe that on the retaining wall.When design the retaining structures under the plane strain state,appropriate formula should be chosen to consider the contribution of the intermediate principal stress so as to give full play of the potential strength of soil and to improve the economic benefits in project construction.
作者
刘瑾
张玉
邵生俊
赵阳
孟天一
佘芳涛
LIU Jin;ZHANG Yu;SHAO Sheng-jun;ZHAO Yang;MENG Tian-yi;SHE Fang-tao(School of Civil and Architecture Engineering,Xi'an Technological University,Xi'an 710021,China;Shaanxi Key Laboratory of Loess Mechanics and Engineering,Xi'an University of Technology,Xi'an 710048,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2021年第S01期30-35,共6页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(11802218)
陕西省科技计划项目(2019JQ-432、2019JQ-835)
陕西省黄土力学与工程重点试验室项目(LEM201801)
陕西省教育厅自然专项科研计划项目(20JK0670)
关键词
平面应变
强度准则
中主应力
土压力
plain strain
strength criterion
intermediate principal stress
earth pressure
作者简介
通信作者:张玉,E-mail:153673438@qq.com
