| 李家卓*,朱传奇,刘万荣.极松软煤层工作面片帮力学机制分析与煤体加固实验研究[J].实验力学,2017,32(4):559~567 |
| 极松软煤层工作面片帮力学机制分析与煤体加固实验研究 |
| Experimental Study of Coal Seam Reinforcement and Mechanism Analysis of Working Surface Rib Spalling for Very Soft Coal Seam |
| 投稿时间：2016-12-27 修订日期：2017-04-03 |
| DOI：10.7520/1001-4888-16-285 |
| 中文关键词: 极松软煤 片帮机理 煤体加固 力学实验 |
| 英文关键词:very soft coal seam mechanism of rib spalling coal seam reinforcement mechanical experiments |
| 基金项目:国家自然科学基金煤炭联合基金重点资助项目(U1361208);安徽省自然科学基金资助项目(1408085MKL42);安徽理工大学博士基金;安徽理工大学青年教师科学研究基金重点项目(12859) |
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| 中文摘要: |
| 针对极松软煤层工作面煤壁片帮控制难题,三维有限差分数值计算表明,极松软煤层开挖后在煤壁底角产生剪应力集中,破坏位置由此沿渐变剪应力带牵引至煤壁顶部,产生卸载松弛浅层坍滑片帮。室内实验结果表明,极松软煤天然含水率极低,自身保水能力严重不足,极易失水。含水率由1.46% 提高到3.39%,应变量增高154.32%;含水率4.49%,粘土含量10.00%。与无粘土极松软煤相比,抗压强度提高55.02%,应变提高574.26%。含水率在0～4.03%内,抗剪强度与含水率正相关;含水率在4.03%～12.70%区间,随着含水率的增高,抗剪强度迅速降低。且黏聚力对水的敏感度远大于内摩擦角对含水率的敏感程度,存在某一特定含水率,此时抗剪强度最大。极松软煤层可采用施工扰动方法,使煤层在工作面前方壳基支承压力作用下发生团化固结,达到有效应力增加、孔隙比减小、抗剪强度提高的目的。 |
| 英文摘要: |
| Aiming at the control problem of working surface coal wall spalling in extremely soft coal seam, three-dimensional finite difference numerical calculation indicates that after excavation of extremely soft coal seam, shear stress concentration occurs at coal wall bottom, then the damage position is drawn to the top of coal wall along the belt of gradual shear stress, thus unloading and relaxation of shallow spalling is generated.Indoor experimental results show that the natural moisture content of very soft coal seam is extremely low, its water holding capacity is seriously insufficient, easy to water loss. Water content increases from 1.46% to 3.39%, the strain value increases by 154.32%; when water content is 4.49%, the clay content is 10.00%. Comparing with very soft coal seam without clay, the compression strength increases by 55.02%, strain increases 574.26%. When the moisture content is within 0~4.03%, the shear strength is positively related to water content. When moisture contents are between 4.03%~12.70%, the shear strength decreases rapidly with the increase of water content. Moreover, the sensitivity of cohesive force to water content is much larger than that of internal friction angle. There is specific moisture content, when the shear strength is the largest. Using construction disturbance method, the very soft coal seam can be consolidated through the effect in front of coal bed shell base pressure support, the effective stress increases, pore ratio decreases, shear strength is improved. |
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