加载速率对煤系泥岩脆-延性转变影响的试验研究  

Experimental research of influence of loading rate on brittle-ductile transition of mudstone in coal rock strata

作　　者：张连英[1,2] 张树娟[1] 茅献彪[2] 汤晓英[3] 秦昊[3] 李兵[1] 李明[2] ZHANG Lianying1＇2, ZHANG Shujuan1, MAO Xianbiao2, TANG Xiaoying3, QIN Hao3, LI Bing1, LI Ming2(1. Civil EngineeringDepartment, XuzhoulnstituteofTechnology, Xuzhou, Jiangsu 221000, China; 2. State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining ＆ Technology, Xuzhou, Jiangsu 221116, China; 3. Shanghai Institute of Special Equipment Inspection and Technical Research, Shanghai 200333, Chin)

机构地区：[1]徐州工程学院土木学院,江苏徐州221000 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116 [3]上海市特种设备监督检验技术研究院,上海200333

出　　处：《采矿与安全工程学报》2018年第2期391-396,401,共7页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金青年项目(51104128);江苏省第四期"333工程"科研项目(BRA2015065)

摘　　要：加载速率会造成岩石材料破坏形态的改变,材料破坏过程中存在脆延性转变的临界速率。为了探讨不同加载速率作用下泥岩的脆延性转化特性,以煤系岩层中泥岩为研究对象,采用MTS810电液伺服材料力学试验系统、FEI Quanta TM250扫描电镜,进行了力学试验和扫描电镜试验,分析了加载速率对泥岩屈服应变、峰值应变、延性系数和应力-应变关系的影响。试验结果表明:随着加载速率的升高,泥岩的屈服应变整体上呈现逐渐上升的趋势;加载速率在0.03 mm/s时泥岩的延性系数增加,岩样破坏体现了一定的延性特征;煤系泥岩在0.03 mm/s的加载速率作用下,其宏观断裂为椎裂和剪切滑移破裂的混合破裂,微观断口形貌既有解理台阶,又有沿晶裂纹和穿晶裂纹,同时存在剪切滑移带,破坏方式趋向于延性,脆性降低。研究结果可为岩土工程问题提供重要依据。The loading rate can result in the change of rock＇s rupture shape. There is a critical velocity during the breakage process of material when brittleness transferring to plasticity. In order to investigate the brittle ductile transformation characteristics of mudstone under different loading rates, the mudstone in coal measure rock strata is chosen as the research object. Using MTS810 electro mechanical hydrau- lic servo test system and FEI Quanta TM250 scanning electron microscope, the mechanical test and SEM test are carried out to analyze the influence of loading rate on the yield strain, peak strain, ductility coefficient and stress-strain relation of mudstone. The results show that： With the increase of loading rate, the yield strain of mudstone shows a trend of gradual increase; the ductility coefficient of mudstone increases when the loading rate is 0.03 mm/s, and the rock failure reflects the ductile feature; At the loading rate of 0.03 mm/s, the macroscopic fracture of mudstone is the mixing of the vertebral fracture and shear rupture. The micro fracture morphology includes both of cleavage, intergranular cracks and trans granular cracks, the shear slip zone existing at the same time, the failure mode tends to ductility and the brittleness ductility reduces. The research results can provide important basis for research on geotechnical engineering problems.

关 键 词：泥岩 加载速率 屈服应变 延性系数 脆延性转变 

分 类 号：TD353[矿业工程—矿井建设]