Experimental Study on Influential Factors for Shear Properties of Interfaces Between Anchor Bolts and Soil Under Different Confining Pressures
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摘要: 为研究土层锚杆锚–土界面力学特性,对锚杆进行室内试验,以预制锚杆和现浇锚杆为研究对象,研究围压、含水率及土体强度对锚杆锚固体–土界面力学特性的影响,同时对两种锚杆的剪切性能进行对比研究,并建立锚杆锚固体–土界面剪应力–剪切位移全过程关系模型。结果表明:围压越高,锚杆剪应力越大,其极限抗拔力越大;锚杆的极限抗拔力随含水率的增大呈先增大后减少的趋势,当土体含水率接近其最优含水率时,锚杆的锚固性能相对较好;土体强度越高,锚杆极限抗拔力越大;现浇锚杆极限抗拔力大于预制锚杆,并随着围压的增大,两种锚杆的极限抗拔力之差越大;两种锚杆破坏形式一致;提出的锚固体–土界面应力–应变关系拟合曲线与试验实测曲线吻合较好。Abstract: In order to study the mechanical properties of the interface between anchor bolts and soil, the pull-out tests on indoor anchor bolts were performed. The effects of confining pressure, water content and soil strength on the mechanical properties the interfaces between anchorage bodies and soil were studied taking precast and cast-in-situ anchor bolts as objects. Simultaneously, the shear properties of the two types of anchor bolts were compared, and the whole process model of shear stress-shear displacement between interfaces of anchorage bodies and soil was proposed. The results indicated that the higher the confining pressures were, the greater the shear stresses of the interfaces and the ultimate pullout forces of anchor bolts were. With the increase in the water content, the ultimate pullout forces of anchor bolts increased first and then decreased, and when the water content of soil closed its optimal water content, the anchorage properties of anchor bolts were relatively better. The higher the soil strength was the greater the ultimate pullout forces of anchor bolts were. The ultimate forces of cast-in-situ anchor bolts were greater than that of precast anchor bolts, and the differences of the ultimate pullout force between the two types of anchor bolts were greater with the increase in confining pressures. The failure modes of the two types of anchor bolts were consistent. The proposed fitting curves of stress-strain relations between interfaces of anchorage bodies and soil were fairly good agreement with the measured curves by tests.
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