附加应力法在无杆钻具稳定性分析中的应用

发布时间：2018-01-19 13:27

本文关键词： 无杆钻具支护结构稳定性附加应力虚拟土柱　出处：《华南理工大学学报(自然科学版)》2017年05期 　论文类型：期刊论文

【摘要】：为使无杆钻具能有效支撑在孔壁土体上,探讨了支护结构施加的预应力对孔壁土体稳定性的影响,提出了采用虚拟土柱模拟桩孔并结合广义Mindlin解的方法,推导了预应力作用下孔壁土体中任一点的附加应力向量.基于此附加应力向量,求取了最大预扭矩和最大预压力作用下支护板下方5 mm、宽50 mm处各点的剪切应力及其相对强度.结果表明:当预扭矩与预应力分别为120 k N·m和100 k N时,最大剪切应力为6.52 MPa;除了支护板两端部外,剪切应力相对强度均小于1,即总体上孔壁土体为稳定状态.与试验结果的对比验证了文中方法的正确性,文中方法比Boussinesq-Gerruti联合求解法和有限元法更加精确
[Abstract]:In order to support the hole wall soil effectively, the influence of the prestressing force applied by the supporting structure on the stability of the hole wall soil is discussed. A method of simulating pile holes with virtual soil columns and combining with generalized Mindlin solution is proposed. The additional stress vector at any point in the soil under prestressing force is derived and based on this additional stress vector. Under the action of maximum pre-torque and maximum pre-pressure, 5 mm below the supporting plate is obtained. The shear stress and relative strength of each point at the width of 50 mm. The results show that when the pre-torque and prestress are 120 KN 路m and 100 KN, respectively. The maximum shear stress is 6.52 MPA; Except for the two ends of the support plate, the relative strength of shear stress is less than 1, that is, the overall soil mass of the hole wall is stable. The comparison with the experimental results verifies the correctness of the method in this paper. The method in this paper is more accurate than Boussinesq-Gerruti combined solution and finite element method.
【作者单位】：哈尔滨工业大学机电工程学院;
【基金】：国家国际科技合作专项(2015DFA70100)~~
【分类号】：TU631
【正文快照】： 无杆钻具[1]钻进土体之前,支护结构预应力通过支护板传递给孔壁土体,进而平衡螺旋钻头所受切削阻力矩和贯入阻力.土体在预应力作用下,其内部的应力状态会发生改变,从而使土体稳定性发生变化[2-6].因此,为了提高孔壁土体的稳定性,保证无杆钻具的正常作业,研究无杆钻具作用下孔

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