预应力锚索地梁结构在边坡稳定中的作用机理

Force transmission law of prestressed anchor-rope and groundsill structure in slope stability

建立受非均布线形荷载作用的地基力学模型,应用叠加原理推导出预应力锚索-地梁结构中垂直于梁轴线平面内的地基中深度z处的应力和位移计算公式,为研究预应力锚索-地梁结构在岩体中的传力规律提供理论依据。以溆怀(湖南溆浦—怀化)高速公路K24+233-K27+89边坡为实险区域研究预应力锚索地梁结构在边坡稳定中的作用机理。研究结果表明:在对锚索施加预应力后,锚索预应力通过地梁传递给被加固的岩土体,在垂直于地梁轴线的平面内,其传递方式以梁轴线与该平面的交点为端点的近似橢圆的等值面形式由内向外呈逐渐衰减趋势分布;两地梁周边岩体中的压应变随深度增加由小到大增至峰值,然后逐渐衰减为0,这种分布形式与理论结论一致。

The force transmission law of a prestressed anchor-rope and the groundsill structure in rock mass were studied. The foundation mechanical model of nonuniform linear unipoium load under the premise of the ground surface suffering nonuniform linear load was established and deduced by the superposition principle, and the calculating formula for the stress and displacement at the depth z in the foundation of the beam axis was deduced for the prestressed anchor-rope and groundsill structure. Taking the slope of K24＋233--K27＋89 of Xupu--Huaihua Expressway as a experimental region, the force transmission law of prestressed anchor-rope and groundsill structure in slope stability were studied. The results show that when the anchor cable is provided with pre-stress, the actual prestress in the prestressed cable anchor can be transferred to the strengthening geotechnical body through the ground beam, of which the transfer mode tends to decay from the inside to the outside in the form of approximate ellipse iso-surface with the endpoints. The intersection of the beam axis and the plane are perpendicular to the axis of the beam. The compressed strain in the peripheral rock of two ground beams tends to increase with the increase of the depth of the anchor, and then tends to decay gradually and finally tends to be 0 after reaching its peak value. This distribution form is in accordance with the theoretical form.