三轴压缩条件下含界面重塑黄土力学特性试验  

Experiment on Mechanical Properties of Interface Loess Under Triaxial Compression

作　　者：马哲 彭建兵[1,2] 赵鲁庆 宁瑞浩 李泽坤 MA Zhe;PENG Jian-bing;ZHAO Lu-qing;NING Rui-hao;LI Ze-kun(School of Geological Engineering and Geomatics,Chang an University,Xi'an 710054,Shaanxi,China;Key Laboratory of Western China s Mineral Resources and Geological Engineering of Ministry of Education,Chang an University,Xi'an 710054,Shaanxi,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]长安大学西部矿产资源与地质工程教育部重点实验室,陕西西安710054

出　　处：《地球科学与环境学报》2022年第6期1027-1036,共10页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金重大项目(41790441)。

摘　　要：黄土细观界面是广泛分布在黄土体中的一种结构缺陷,是黄土灾变的重要控制因素。为探究细观界面对黄土力学行为的影响,在土样侧壁标注网络剖分线,开展预制界面重塑黄土常规三轴压缩试验,获取破坏后试样侧壁网络剖分线,分析不同位置细观界面对土体强度及变形破坏特征的影响。结果表明:①试样变形主要分为轴向变形和弯曲变形,并以轴向变形为主;破坏方式以“X”型破坏和45°剪切破坏为主;根据破坏形态、破坏规模和破坏后应力-应变曲线类型,将破坏后的侧壁网络剖分线分为弱硬化型、屈服后弱硬化型、软化型和双峰值强软化型4种类型。②试样应力-应变曲线以软化型为主,受细观界面位置及围压影响。围压为300 kPa时,中部界面土样表现为弱硬化型;围压为100 kPa时,中部界面土样表现为屈服后弱硬化型,顶部和底部界面土样表现为双峰值强软化型。③中部界面对土样强度的劣化作用最强,顶、底部界面次之。细观界面黄土的应力-应变特性和变形破坏特征,受界面位置、试验围压等因素共同影响,研究成果可为进一步研究细观界面黄土强度准则,揭示细观界面对黄土灾变机理提供参考。Loess meso-interface is a structural defect widely distributed in loess,and is an important control factor for loess catastrophe.In order to find the influence of meso-interface on the mechanical behavior of loess,the network subdivision line was marked on the sidewall of the soil sample,and the conventional triaxial compression test of loess remodeled by the prefabricated interface was carried out,and the network subdivision of the sidewall of the sample after failure was obtained;the influences of meso-interfaces at different positions on soil strength and deformation and failure characteristics were analyzed.The results show that①the deformation of the sample is mainly divided into axial deformation and bending deformation,and the main deformation is axial;the failure mode is mainly“X”type and 45°shear;according to the failure form,failure scale and stress-strain curve type after failure,the network subdivision line of the sidewall after failure is divided into 4 types,including weak hardening type,weak hardening type after yielding,softening type and double-peak strong softening type;②the stress-strain curve of the sample is mainly softening type,which is affected by the position of the meso-interface and the confining pressure;when the middle interface of soil samples shows weak hardening type after yielding,and the top and bottom interfaces of soil samples show double-peak strong softening type;③the middle interface of soil sample has the strongest degradation effect on the soil strength,followed by the top and bottom interfaces.The stress-strain,deformation and failure characteristics of meso-interface loess are affected by the interface position,test confining pressure and other factors.The above results can provide a reference for the further research of the meso-interface loess strength criterion and the mechanism of meso-interface on the loess disaster.

关 键 词：细观界面 马兰黄土 三轴压缩 应力-应变 变形规律 破坏特征 陕西 

分 类 号：P642[天文地球—工程地质学]