树脂锚杆锚固段剪应力分布及其损伤模式分析

Distribution of shear stress on resin bolt of anchoring rods and its damage model analysis

为了分析树脂锚杆锚固段剪应力分布及其承载、损伤机理,提高树脂锚杆支护在煤矿现场应用的有效性,首先根据煤矿树脂锚杆的围岩环境和受力特点,基于集中载荷作用于半无限体表面和无限体内部的弹性力学解得到了树脂锚杆在非锚固段围岩破碎和完整时的锚固段锚固界面剪应力计算式,分析了锚杆杆体拉力在锚固段锚固界面的剪应力形成机理;然后采用FLAC数值模拟软件模拟了树脂锚杆锚固段的承载及变形,得到了树脂锚杆在一定载荷和围压作用下锚固界面塑性发展趋势;最后以混凝土试块模拟围岩,并在混凝土试块预留孔中锚固了树脂锚杆进行实验室拉拔试验,得到了树脂锚杆锚固段剪应力分布及其增加趋势.结果表明,树脂锚杆剪应力开始时呈负指数形态分布,随着锚杆拉应力的增大,锚固起始端剪切破坏剪应力降低,无围压时峰值剪应力迅速向较深部锚固界面移动并锚固失效,有围压时锚固界面在锚固起始端剪切破坏后仍有较大的锚杆拉应力发展范围.

In order to analysis the distribution, loading and damage mechanism of resin anchoring bolt anchorage shear stress, and to improve the effectiveness of the application of resin bolt support in coal mine field. According to the surrounding environment and the mechanical characteristics of resin anchoring bolt in coal mine, based on the elastic mechanics solution of concentrates on load ACTS on the surface of semi - infinite body and infinite internal body, that of shear stress calculation formula of anchorage, resin anchoring bolt in the anchoring of surrounding broken and full of the anchoring interface, was gotten and then shear stress formation mechanism, that of the anchor rod body tension in the interface of anchoring anchorage, was analysized; By using the FLAC numerical simulation software to simulate the bearing and deformation of resin anchoring bolt anchorage segment, the development trend, which of plastic under the action of anchorage interface of resin anchor rod under certain load and confining pressure, was revealed. The distribution of shear stress was revealed, that of resin bolt＇ s anchorage section by a lab pull - out test, which uses concrete to simulate surrounding rock, and anchorages resin bolting in concrete preformed -hole. The results show that the shear stress of resin anchoring bolt is negative exponent form distribution at first. With the increasing of anchor stress, shear failure and shear stress in the anchoring start section is reducing, and when there is no confining pressure, peak shear stress moves quickly to a deep anchorage interface and invalidation, when there is confining pressure, anchoring interface in anchorage between shearing failure still has a bigger bolt tensile stress development scope.