低温冻结状态下岩石的变形特性及力学行为研究

兰州理工大学学报 ›› 2022, Vol. 48 ›› Issue (2): 21-27.

低温冻结状态下岩石的变形特性及力学行为研究

席新林^*

中铁第一勘察设计院集团有限公司, 甘肃兰州 730000

收稿日期:2021-11-18 出版日期:2022-04-28 发布日期:2022-05-07
通讯作者: 席新林(1971-),男,甘肃定西人,高级工程师.Email:195618029@qq.com
基金资助:
甘肃省科技重大专项(1102GKDA053)

Study on deformation characteristics and mechanical behavior of rock under low temperature freezing state

XI Xin-lin

China Railway First Survey And Design Institute Group Co, Ltd., Lanzhou 730000, China

Received:2021-11-18 Online:2022-04-28 Published:2022-05-07

摘要/Abstract

摘要： 为研究冻土地区不同含水状态下冻结岩石的力学行为,对凝灰岩和玄武岩冻土试件进行了常温20 ℃和低温－20 ℃下的单轴压缩试验和巴西劈裂试验.通过观察其变形行为和声发射活动,研究了其断裂破坏过程以及饱水率对材料强度和变形性能的影响.结果表明,冻结岩石的破裂过程分为以下几个阶段:Ⅰ阶段为裂纹气孔闭合;Ⅱ阶段为弹性变形;Ⅲ阶段为裂缝起裂与稳定裂缝扩展;Ⅳ阶段为裂缝不稳定扩展.同时,Ⅲ阶段开始处的应力水平随着饱水率的增加而增加.峰值应力强度和应变均随着饱水率的增加而增加,它们之间的关系可以用直线来近似表示.岩石脆性度随饱水率的增加而降低,间接抗拉强度对饱水率的影响比单轴抗压强度更敏感.

关键词: 冻结岩石, 饱水率, 抗压强度, 抗拉强度, 变形, 声发射, 破坏过程

Abstract: In order to study mechanical behaviorof frozen rock under different water content in frozen soil area, the uniaxial compression test and Brazilian splitting test of tuff and basalt frozen soil specimens at room temperature 20 ℃ and low temperature －20 ℃ were carried out. By observing its deformation behavior and acoustic emission activity, the fracture failure process and the effect of water content on the strength and deformation properties of the material were studied. The results showed,the fracture process of frozen rock can be divided into the following stages:Ⅰ stage is crack pore closure;Ⅱ stage is elastic deformation;Ⅲ stage is crack initiation and stable crack propagation;Ⅳ stage is unstable crack propagation. At the same time, the stress level at the beginning of stage Ⅲ increases with the increase of water saturation. The peak stress intensity and strain increase with the increase of water content, and the relationship between them can be approximated by a straight line. Rock brittleness decreases with the increase of water content, and the influence of indirect tensile strength on water content is more sensitive than uniaxial compressive strength.

Key words: frozen rock, water content, compressive strength, tensile strength, deformation, acoustic emission, failure process

中图分类号:

TB121

席新林. 低温冻结状态下岩石的变形特性及力学行为研究[J]. 兰州理工大学学报, 2022, 48(2): 21-27.

XI Xin-lin. Study on deformation characteristics and mechanical behavior of rock under low temperature freezing state[J]. Journal of Lanzhou University of Technology, 2022, 48(2): 21-27.

参考文献

[1] JIA H,LEITH K,KRAUTBLATTER M.Path-dependent frost-wedging experiments in fractured,low-permeability granite s [J].Permafrost and Periglacial Processes,2017,28(4):698-709.
[2] TAN X,CHEN W,LIU H,et al.A unified model for frost heavepressure in the rock with a penny-shaped fracture during
freezing [J].Cold Regions Science and Technology,2018,153:1-9.
[3] 魏尧,杨更社,叶万军,等.冻融黄土无侧限抗压强度的析因实验 [J].西安科技大学学报,2019,39(1):103-111.
[4] 赵涛,杨更社,奚家米,等.白垩系砂岩宏细观冻融损伤特性试验研究 [J].西安科技大学学报,2019,39(2):241-248.
[5] 汤贵海,伍毅敏,张镇国,等.寒区隧道层间聚氨酯保温板的冻融特性试验 [J].西安科技大学学报,2018,38(2):323-329.
[6] 李杰林,刘汉文,周科平,等.冻融作用下岩石细观结构损伤的低场核磁共振研究 [J].西安科技大学学报,2018,38(2):266-272.
[7] 薛翊国,孔凡猛,杨为民,等.川藏铁路沿线主要不良地质条件与工程地质问题 [J].岩石力学与工程学报,2020,39(3):445-468.
[8] 于雪飞,熊治文,武小鹏,等.青藏铁路修筑后次生不良冻土现象的特征及发展趋势 [J].铁道标准设计,2016,60(7):43-46.
[9] 程佳,王涛,朱兆荣,等.青藏铁路风火山地段路基病害特征及防治措施研究 [J].铁道标准设计,2015,59(8):14-17.
[10] 温立光,曾帅,张守超,等.严寒地区铁路路基防冻胀改良土封闭层控制标准研究 [J].铁道建筑,2021,61(7):85-88.
[11] 蒋应军,王翰越,乔怀玉,等.水、干湿及冻融循环作用下水泥改良黄土路基稳定性 [J].科学技术与工程,2020,20(35):14592-14599.
[12] 毕贵权,穆丽静,王冬.兰州地铁沿线粉质黏土的冻胀融沉特性 [J].兰州理工大学学报,2018,44(2):113-116.
[13] 毕贵权,张侠,李国玉,等.冻融循环对黄土物理力学性质影响的试验 [J].兰州理工大学学报,2010,36(2):114-117.
[14] PARK C,SYNN J H,SHIN H S,et al.Experimental study on the thermal characteristics of rock at low temperatures [J].International Journal of Rock Mechanics ＆ Mining Science,2004,4(S1):81-86.
[15] 杨更社.冻结岩石力学的研究现状与展望分析 [J].力学与实践,2009,31(6):9-16,29.
[16] 杨更社,奚家米,李慧军,等.三向受力条件下冻结岩石力学特性试验研究 [J].岩石力学与工程学报,2010,29(3):459-464.
[17] 张辛亥,张康,丁峰,等.低温下煤岩体力学特性实验研究 [J].煤矿安全,2016,47(1):41-43.
[18] 张丛峰,谢骏腾,宋林.严寒地区高速铁路基岩冻胀试验研究 [J].公路交通科技,2013,9(6):248-249,260.
[19] 徐光苗.寒区岩体低温、冻融损伤力学特性及多场耦合研究 [J].岩石力学与工程学报,2007(5):1078.