端部约束作用下巷旁支护体承载与破坏规律研究

发布时间：2018-11-15 18:05

【摘要】：为了预测不同端部条件及不同煤层倾角下巷旁支护体的变形和破坏规律,利用FLAC3D构建巷旁支护体模型,通过试算法,获得模型内聚力和内摩擦角随塑性剪切应变的折减函数关系,使数值模型与充填材料在物理压缩试验中获得的应力-应变关系和破坏规律一致。基于该种赋值条件,对巷旁支护体在不同端部条件下的变形破坏规律进行研究,获得以下结论:无端部约束下,峰前支护体内的应力分布近似均匀,可自由侧向变形,且倾角对支护体进入塑性时的峰值载荷大小没有明显影响;存在端部效应时,支护体的峰值承载能力有所提高,并将在侧向产生非均匀变形。在端部约束条件下,随着倾角的变化,支护体的破坏形式不同:当倾角为0°~10°时,呈现多重剪切破坏;10°~25°时,呈现双裂隙的剪切破坏;25°时,边界单元呈现摩擦剪切破坏。此外,在倾角作用下,存在端部约束时,在支护体的锐角处应力集中程度最高,在进行支护设计时应补强支护。
[Abstract]:In order to predict the deformation and failure law of the side support of roadway with different end conditions and different inclined angles of coal seam, the model of side support of roadway was constructed by FLAC3D, and the trial algorithm was used. The reduction function of cohesive force and internal friction angle with plastic shear strain is obtained, and the stress-strain relationship and failure law obtained by the numerical model are consistent with those obtained in the physical compression test of the filling material. Based on this assignment condition, the deformation and failure law of roadway side support body under different end conditions is studied. The following conclusions are obtained: the stress distribution in front of peak support is approximately uniform and free lateral deformation can be obtained under no end restraint. And the angle of inclination has no obvious influence on the peak load when the support body enters the plasticity. In the presence of end effect, the peak bearing capacity of the supporting body is increased, and the lateral deformation will be uneven. Under the constraint condition of the end, with the change of the inclination angle, the failure forms of the support body are different: when the inclination angle is 0 掳~ 10 掳, it presents multiple shear failure; when the slope angle is 0 掳~ 10 掳, it presents the shear failure of double fractures; at 25 掳, the boundary element presents friction shear failure. In addition, under the action of inclination angle, the stress concentration at the sharp angle of the support body is the highest when the end constraint exists, and the support should be strengthened when the support design is carried out.
【作者单位】：重庆大学煤矿灾害动力学与控制国家重点实验室资源及环境科学学院;
【基金】：国家自然科学基金项目(51474039,51404046) 重庆大学煤矿灾害动力学与控制国家重点实验室自主课题项目(2011DA105287 ZD201302) 重庆市研究生科研创新项目(CYS15007)
【分类号】：TD353

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