【作者】 邱贤辉；

【导师】 黄生文；

【作者基本信息】 长沙理工大学 ， 岩土工程， 2008， 硕士

【摘要】 土钉支护技术在岩体加固工程中应用广泛,土钉作为支护结构的核心应具有足够的安全度和耐久性。由于钢材易腐蚀,钢筋土钉的耐久性受到质疑。GFRP(玻璃纤维增强塑料,Glass Fiber Reinforced Polymer)筋材是一种由树脂和玻璃纤维复合而成的新型加固材料,具有较好的力学性能和耐腐蚀性能,用其替代传统钢筋用于边坡加固可以很好地解决土钉的永久性问题。目前,对于GFRP土钉的研究和应用相对较少,相关的试验数据与研究成果有限。本文研究设计了系列GFRP筋杆体拉伸试验、抗剪切试验、螺纹与螺母之间的承载力试验以及GFRP筋材与砂浆间的拉拔试验,评价了GFRP杆体的抗拉强度、弹性模量及抗剪切强度,结合修正的混合定律模型和引入的尺寸修正因子,建立了GFRP杆体的抗拉强度和弹性模量的预测公式;在拉拔试验的基础上,对GFRP筋材与砂浆的拉拔承载力、平均粘结强度随杆体直径的变化和砂浆强度等级的变化进行分析评价;并基于Mindlin位移解,推导了弹性状态内在荷载作用下锚固体的轴力分布函数和粘结界面应力分布函数,分析了锚固体加筋杆体轴力和粘结界面应力的分布形态;以围岩强化理论对GFRP土钉加固机理进行了理论分析,分别研究了土钉对锚固复合体轴向、横向弹性模量和泊松比,以及抗拉强度的影响变化规律。建立GFRP土钉锚固系统轴对称有限元模型,应用有限元软件ANSYS模拟了锚固体锚固界面应力的分布规律,并分析了在不同岩体的弹性模量和不同围压下,锚固界面应力的变化规律等。最后通过GFRP土钉在边坡工程中的应用实例,分析了GFRP土钉的工程经济性,监测了土钉的应力变化,评价了土钉和边坡的工作状况,实践证明GFRP土钉替代钢筋土钉用于边坡支护是可行的。更多还原

【Abstract】 Soil nailing is a support technology widely used in slope engineering, tunnel and large cave support. As the main part of the support structure, the soil nail must have enough reliability. However, steel bar is easily eroded by environment, so the durability of commonly used steel soil nailing should be paid attention to. The glass fiber reinforced polymer(GFRP) rod, which has better mechanical properties and corrosion resistance is a new kind of reinforcement material compounded with resin and glass fiber. The durability problem in slope engineering can be solved if the GFRP soil nail takes the place of steel bars.However there is little research being done on GFRP soil nailing, and related experimental data and research results are very limited. In this dissertation, serials tests such as tensile strength and shear strength of GFRP rod, bearing capacity between thread and nut are conducted. The assessment of tensile strength, elastic modulus and shear strength on GFRP rod are made. By introducing a modified factor of dimension, combined with modified model of mixture, prediction formula of tensile strength and elastic modulus of GFRP rod are build respectively. Based on the results of pullout tests, the bond behavior of GFRP bolts, including bearing capacity, average bond strength with variation of rod diameter and strength grade of mortar were evaluated. Meanwhile, based on the Mindlin solution, the dissertation deduced the stress distribution functions of anchored rock mass under loadings, analyzed the distribution form of axial force of rod and stress of anchoring interface. Theoretical analysis about reinforcement mechanism of GFRP soil nailing is conducted with strength enhancement theory of surrounding rock. The variation regulation of parameters, including axial elastic modulus, transverse elastic modulus, axial poison ratio, transverse poison ratio and tensile strength of anchoring complex were studied respectively.This dissertation builds axisymmetric element model of GFRP soil nailing anchorage system. With the usage of Finite Element Method(FEM) software ANSYS, the shear stress distribution of the anchoring interface is simulated, and the variation regulations of stress distribution of anchored rock mass with different elastic modulus and different confining pressure are also simulated.Finally, with an application case of GFRP soil nailing used in a slope engineering, the engineering economics of GFRP soil nailing is analyzed compared with steel soil nailing. Stress variations of GFRP soil nails are monitored, and the working situation of both the soil nails and the slope are appraised. It is feasible that GFRP soil nail takes the place of steel soil nail to support slope.更多还原