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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。
In order to predict the deformation and failure of roadside supports with different end conditions and coal seam inclination, the model of roadside support was constructed by using FLAC3D, and the reduction function of cohesion and internal friction angle with plastic shear strain Relationship between the numerical model and the filling material in the physical compression test obtained stress-strain relationship and failure consistent. Based on this kind of assignment conditions, the law of deformation and failure of roadside support body under different end conditions is studied, and the following conclusions are obtained: under the condition of no end constraint, the stress distribution in the front support body is nearly uniform and free to deform laterally, And the inclination angle has no obvious influence on the peak load when the support body enters the plasticity. When there is the end effect, the peak load bearing capacity of the support body is increased, and the non-uniform deformation will occur in the lateral direction. Under the condition of end restraint, the failure forms of support body vary with the dip angle: when shear angle is 0 ° ~ 10 °, multiple shear failure occurs; at 10 ° ~ 25 °, shearing with double cracks Damage;> 25 °, the boundary elements exhibit frictional shear failure. In addition, under the action of dip angle, when there is end constraint, the stress concentration is the highest at the acute angle of support body, and the support should be reinforced during the support design.