Experimental study of strength characteristics of water-saturated coal specimens under 3D coupled static-dynamic loadings
WANG Wen1，2，3，LI Huamin1，GU Helong1
(1. School of Energy Science Engineering，Henan Polytechnic University，Jiaozuo，Henan 454003，China；
2. Research Center of Coal Resources Safe Mining and Clean Utilization，Liaoning Technical University，Fuxin，Liaoning 123000，China；3. Shanxi Coal Import and Export Group Co.，Ltd.，Taiyuan，Shanxi 030006，China)
Abstract：In order to study the mechanical properties of water-saturated coal specimens under coupled static-dynamic loadings，contrast experiments between 3D coupled static-dynamic loadings and 3D static loadings on both water-saturated coal specimens and natural coal specimens were conducted by using the improved split Hopkinson pressure bar(SHPB) and the RMT–150 test systems. Results shows that，under 3D static loadings，the variation of peak strength of natural coal specimens is 10.49%，while the variation of peak strength of 7 d saturated specimen is 59.98%，with a softening coefficient of 0.81. Under 3D coupled static-dynamic loadings，when the axial pressure is less than 55% of the uniaxial compression strength，the dynamic strengths of the 7 d saturated coal specimens are higher than those of the natural coal specimens，the increased strength of 7 d saturated coal specimens are 7.85%–18.44%(confining pressure 4 MPa) or 8.71%–19.84%(confining pressure 4 MPa) compared to the natural coal specimens. In the case of different confining pressures with the same axial pressure，with the increase of confining pressure，the dynamic strengths of the 7 d saturated and the natural specimens are both increased. Moreover，the increment of dynamic intensity of 7 d saturated coal specimens is larger than that under the natural state，indicating that water-saturated coal specimens are more sensitive to confining pressure. Experimental results show that the effect of water-saturation to the strength of coal specimen is significant，but the strain rate plays a controlling role. The coupling effect between the water and coal fissure causes the larger stiffness under the conditions of medium or high strain rate. The dynamic strength of water-saturated coal specimens increases under 3D static-dynamic loadings.
王 文1，2，3，李化敏1，顾合龙1. 三维动静组合加载含水煤样强度特征试验研究[J]. 岩石力学与工程学报, 2017, 36(10): 2406-2414.
WANG Wen1，2，3，LI Huamin1，GU Helong1. Experimental study of strength characteristics of water-saturated coal specimens under 3D coupled static-dynamic loadings. , 2017, 36(10): 2406-2414.
[1] 黄理兴. 岩石动力学研究成就与趋势[J]. 岩土力学，2011，32(10)：2 889–2 900.(HUANG Lixing. Development and new achievements of rock dynamics in China[J]. Rock and Soil Mechanics，2011，32(10)：2 889–2 900.(in Chinese))
[2] 钱七虎. 地下工程建设安全面临的挑战与对策[J]. 岩石力学与工程学报，2012，31(10)：1 945–1 956.(QIAN Qihu. Challenges faced by underground projects construction safety and countermeasures[J]. Chinese Journal of Rock Mechanics and Engineering，2012，31(10)：1 945–1 956.(in Chinese))
[3] 姜耀东，潘一山，姜福兴，等．我国煤炭开采中的冲击地压机理和防治[J]. 煤炭学报，2014，39(2)：205–213.(JIANG Yaodong，PAN Yishan，JIANG Fuxing，et al. State of the art review on mechanism and prevention of coal bumps in China[J]. Journal of China Coal Society，2014，39(2)：205–213.(in Chinese))
[4] 何满潮，谢和平，彭苏萍，等. 深部开采岩体力学研究[J]. 岩石力学与工程学报，2005，24(16)：2 803–2 813.(HE Manchao，XIE Heping，PENG Suping，et al. Study on rock mechanics in deep mining engineering[J]. Chinese Journal of Rock Mechanics and Engineering，2005，24(16)：2 803–2 813.(in Chinese))
[5] 马春德，李夕兵，陈 枫，等. 单轴动静组合加载对岩石力学特性影响的试验研究[J]. 矿业研究与开发，2004，24(4)：1–4.(MA Chunde，LI Xibing，CHEN Feng，et al. Test and study of mechanical properties of rock under uniaxial static and dynamic coupling loads[J]. Mining Research and Development，2004，24(4)：1–4.(in Chinese))
[6] 左宇军，李夕兵，唐春安，等. 二维动静组合加载下岩石破坏的试验研究[J]. 岩石力学与工程学报，2006，25(9)：1 809–1 820.(ZUO Yujun，LI Xibing，TANG Chun?an，et al. Experimental investigation on failure of rock subjected to 2D static-dynamic coupling loads[J]. Chinese Journal of Rock Mechanics and Engineering，2006，25(9)： 1 809–1 820.(in Chinese))
[7] 宫凤强，李夕兵，刘希灵. 三维动静组合加载下岩石力学特性试验初探[J]. 岩石力学与工程学报，2011，30(6)：1 179–1 190.(GONG Fengqiang，LI Xibing，LIU Xiling. Preliminary experimental study of characteristics of rock subjected to 3D coupled static and dynamic loads[J]. Chinese Journal of Rock Mechanics and Engineering，2011，30(6)：1 179–1 190.(in Chinese))
[8] 金解放，李夕兵，钟海兵. 三维静载与循环冲击组合作用下砂岩动态力学特性研究[J]. 岩石力学与工程学报，2013，32(7)：1 358–1 372. (JIN Jiefang，LI Xibing，ZHONG Haibing. Study of dynamic mechanical characteristic of sandstone subjected to three-dimensional coupled static-cyclic impact loadings[J]. Chinese Journal of Rock Mechanics and Engineering，2013，32(7)：1 358–1 372.(in Chinese))
[9] 宫凤强，李夕兵，刘希灵. 三轴SHPB加载下砂岩力学特性及破坏试验研究[J]. 振动与冲击，2012，31(8)：29–32.(GONG Fengqiang，LI Xibing，LIU Xiling. Tests for sandstone mechanical properties and failure model under triaxial SHPB loading[J]. Journal of Vibration and Shock，2012，31(8)：29–32.(in Chinese))
[10] 叶洲元，李夕兵，周子龙，等. 三轴压缩岩石动静组合强度及变形特征的研究[J]. 岩土力学，2009，30(7)：1 981–1 986.(YE Zhouyuan，LI Xibing，ZHOU Zilong，et al. Static-dynamic coupling strength and deformation characteristics of rock under triaxial compression[J]. Rock and Soil Mechanics，2009，30(7)：1 981– 1 986.(in Chinese))
[11] 何满潮，刘冬桥，宫伟力，等. 冲击岩爆试验系统研发及试验[J]. 岩石力学与工程学报，2014，33(9)：1 729–1 739.(HE Manchao，LIU Dongqiao，GONG Weili，et al. Development of a testing system for impact rockbursts[J]. Chinese Journal of Rock Mechanics and Engineering，2014，33(9)：1 729–1 739.(in Chinese))
[12] 何满潮，苗金丽，李德建，等. 深部花岗岩试样岩爆过程实验研究[J]. 岩石力学与工程学报，2007，26(5)：865–876.(HE Manchao，MIAO Jinli，LI Dejian，et al. Experimental study on rockburst processes of granite specimen at great depth[J]. Chinese Journal of Rock Mechanics and Engineering，2007，26(5)：865–876.(in Chinese))
[13] HUANG S，XIA K W，YAN F，et al. An experimental study of the rate dependence of tensile strength softening of Longyou sandstone[J]. Rock Mechanics and Rock Engineering，2010，43：677–683.
[14] ZHOU Z L，CAI X，CAO W Z，et al. Influence of water content on mechanical properties of rock in both saturation and drying processes[J]. Rock Mechanics and Rock Engineering，2016，49： 3 009–3 025.
[15] 王 斌，李夕兵，尹土兵，等. 饱水砂岩动态强度的SHPB试验研究[J]. 岩石力学与工程学报，2010，29(5)：1 003–1 009.(WANG Bin，LI Xibing，YIN Tubing，et al. Spilt Hopkinson pressure bar(SHPB) experiments on dynamic strength of water-saturated sandstone[J]. Chinese Journal of Rock Mechanics and Engineering，2010，29(5)：1 003–1 009.(in Chinese))
[16] 王 文，李化敏，袁瑞甫，等. 动静组合加载含水煤样的力学特征及细观力学分析[J]. 煤炭学报，2016，41(3)：611–617.(WANG Wen，LI Huamin，YUAN Ruifu，et al. Micromechanics analysis and mechanical characteristics of water-saturated coal specimens under coupled static-dynamic loads[J]. Journal of China Coal Society，2016，41(3)：611–617.(in Chinese))
[17] 王 文，李化敏，顾合龙，等. 动静组合加载含水煤样能量耗散特征分析[J]. 岩石力学与工程学报，2015，34(增2)：3 965–3 971. (WANG Wen，LI Huamin，GU Helong，et al. Feature analysis of energy dissipation of water-saturated coal specimens under coupled static-dynamic loads[J]. Chinese Journal of Rock Mechanics and Engineering，2015，34(Supp.2)：3 965–3 971.(in Chinese))
[18] LI X B，ZHOU Z L，LOK T S，et al. Innovative testing technique of rock subjected to coupled static and dynamic loads[J]. International Journal of Rock Mechanics and Mining Sciences，2008，45(5)：739–748.
[19] 宫凤强. 动静组合加载下岩石力学特性和动态强度准则的试验研究[博士学位论文][D]. 长沙：中南大学，2010.(GONG Fengqiang. Experimental study of rock mechanical properties under coupled static-dynamic loads and dynamic strength criterion[Ph. D. Thesis][D]. Changsha：Central South University，2010.(in Chinese))
[20] ROSS C A，JEROME D M，TEDESCO J W，et al. Moisture and strain rate effects on concrete strength[J]. ACI Material Journal，1996，93(3)：293–300.
[21] 王海龙，李庆斌. 饱和混凝土静动力抗压强度变化的细观力学机理[J]. 水利学报，2006，37(8)：958–962.(WANG Hailong，LI Qingbin. Micro-mechanism of static and dynamic strengths for saturated concrete[J]. Journal of Hydraulic Engineering，2006，37(8)：958–962.(in Chinese))
[22] 王海龙，李庆斌. 不同加载速率下干燥与饱和混凝土抗压性能试验研究分析[J]. 水力发电学报，2007，26(1)：84–89.(WANG Hailong，LI Qingbin. Experiments of the compressive properties of dry and saturated concrete under different loading rates[J]. Journal of Hydroelectric Engineering，2007，26(1)：84–89.(in Chinese))
[23] 王海龙，李庆斌. 湿态混凝土抗压强度与本构关系的细观力学分析[J]. 岩石力学与工程学报，2006，25(8)：1 531–1 536.(WANG Hailong，LI Qingbin. Mesomechanics analysis of compressive strength and constitutive equation of wet concrete[J]. Chinese Journal of Rock Mechanics and Engineering，2006，25(8)：1 531–1 536.(in Chinese))
[24] 袁 璞，马瑞秋. 不同含水状态下煤矿砂岩SHPB试验与分析[J]. 岩石力学与工程学报，2015，34(增1)：2 888–2 893.(YUAN Pu，MA Ruiqiu. Split Hopkinson pressure bar tests and analysis of coalmine sandstone with various moisture contents[J]. Chinese Journal of Rock Mechanics and Engineering，2015，34(Supp.1)：2 888– 2 893.(in Chinese))
[25] 孔晓璇. 单裂隙水流对岩体裂隙法向刚度的影响研究[J]. 地下空间与工程学报，2016，12(6)：1 491–1 496.(KONG Xiaoxuan. Influence of single fracture flow on the rock fissures normal stiffness[J]. Chinese Journal of Underground Space and Engineering，2016，12(6)：1 491–1 496.( in Chinese))
2017, Vol. 36 
