增湿-冻融劣化原状黄土的结构强度模型  

Structural Strength Deterioration Model of Undisturbed Loess by Moistening and Freezing-thawing

作　　者：折海成 胡再强[1] 王凯 梁志超 冯哲 郭婧 SHE Hai-cheng;HU Zai-qiang;WANG Kai;LIANG Zhi-chao;FENG Zhe;GUO Jing(Institute of Geotechnical Engineering,Xi an University of Technology,Xi an 710048,China;Key Laboratory of Failure Mechanism and Safety Control Techniques of Earth-rock Dam of the Ministry of Water Resource,Nanjing 210024,China;Institute of Architecture and Civil Engineering,Yulin University,Yulin 719000,China)

机构地区：[1]西安理工大学岩土工程研究所,西安710048 [2]水利部土石坝破坏机理与防控技术重点实验室,南京210024 [3]榆林学院建筑工程学院,榆林719000

出　　处：《科学技术与工程》2020年第18期7378-7386,共9页Science Technology and Engineering

基　　金：国家自然科学基金(51674200,51868075);陕西省科技统筹创新工程重点实验室项目(2014SZS15-Z02);水利部土石坝破坏机理与防控技术重点实验室开放基金(YK916006)。

摘　　要：黄土结构强度是由内部颗粒的空间构型而产生的一种胶结性的联结强度。该强度极易受外界环境的扰动,如增湿、冻融等,引起体积和孔隙变化,削弱黄土的结构强度,进而会影响路堤、边坡、护栏等黄土建筑物的稳定性。首先,通过利用压缩曲线定义黄土结构强度、剩余结构强度和损伤变量等概念,并从深层机理上阐述了损伤变量可表征黄土结构强度劣化过程。其次,基于Weibull分布和损伤力学应变等价性假设,建立了以体积膨胀率作为考察变量的黄土增湿统计损伤模型和增湿-冻融循环耦合统计损伤模型,损伤演化函数及黄土结构强度统计损伤基本方程,并在试验数据的基础上,确定了模型参数。最后,取西安北郊某基坑对黄土统计损伤模型进行验证,与试验吻合性较好。研究成果能方便指导工程设计和现场施工。The structural strength of loess is a kind of cemented bond strength produced by the spatial configuration of internal particles. This strength is easily disturbed by the external environment, such as moistening, freeze-thaw, etc., which will cause changes in volume and porosity, weaken the structural strength of loess, and then affect the stability of embankment, slope, guardrail, and other loess constructions. Therefore, the concepts of loess structural strength, residual structural strength, and damage variable were defined first by using compression curves.And from the deep mechanism, the damage variable could characterize the deterioration process of loess structural strength. Secondly, based on Weibull distribution and damage mechanics strain equivalence hypothesis, the loess statistical damages models of moistening and freezing-thawing cycles coupling action, damage evolution function and basic equation of loess structural strength damage were established with volumetric expansion rate as the investigate variable, and on the basis of the test data, the model parameters were determined, Finally, the models were verified by taking a foundation pit loess in northern suburbs of Xi’an, and were in good agreement with the test. Research results can guide for engineering design and on-site construction.

关 键 词：原状黄土 结构强度 增湿与冻融 损伤变量 统计损伤模型 

分 类 号：TU444[建筑科学—岩土工程]