岩锚解耦测试及其边坡稳定性计算

通过分析边坡坡体在锚固预应力作用下的受力特点，认为应将边坡稳定性计算分为锚固体与坡体的耦合和解耦2个阶段进行，并分析了解耦阶段、锚固力的组成及其作用特点。分析结果表明，解耦阶段的锚固力大小与边坡不稳定体沿潜在的弱面位移有直接关系。结合预应力锚索框架加固边坡的实际特点，进行锚索拉力及梁底土压力的长期观测，验证解耦阶段的实际存在。将锚固体与坡体解耦阶段边坡所受的锚固力分为原锚索预应力的剩余值和岩土体与灌浆体间的剪切阻力，并假设边坡土体均匀、锚固边坡体系是一个平面应变问题，从而导出以岩土体沿潜在滑面位移为基础的解耦阶段边坡稳定性计算方法。该方法考虑边坡和锚索的实际工作状态，故计算结果较以往算法更切合实际，并给出实际算例加以验证。

TEST OF DECOUPLING BETWEEN ROCK MASS AND ANCHORS FOR SLOPE AND ITS STABILITY CALCULATION

By analyzing the mechanical characteristics of prestressed bearing of the slope body, the stability of prestressed anchored slope should be calculated according to coupling and decoupling between slope body and anchors, respectively. The characteristics and the composing of the anchoring forces in decoupling moment are studied. The long-term observations are developed on a practical slope engineering reinforced by prestressed-cable frame; and the tension forces in the cables and earth pressure along the beam bottoms are synchronistically measured, which are founded in existence of the decoupling between slope body and anchors. The practical slope engineering lies in the Yuanjiang--Mohei Expressway of Yunnan Province, China. In fact, the value of the anchoring force in decoupling moment has a close harmonic connection with the displacement of the unstable mass along the underlying weaker plane. The conclusion can be drawn from the theoretical analysis and the long-term observations that the anchoring force in decoupling moment is made up of the residual prestressed force and the shearing resistance between soil and grouting. On the assumption that the slope body is homogeneous and that the prestressing anchored slope is a plane strain system considering the groundwater, secondary forces and the bending of the anchor cables, the calculation method of the slope stability in decoupling moment is then advanced on the basis of the displacements of the soil along the potential sliding surface. The proposed calculation method can consider the actually working conditions of the anchor cables and the slope body, so it has the advantages against existing methods; and the result achieved from the new method is more reasonable. A case study proves the feasibility of the new method.