Design and Application of Pre-support for Bedding Cutting Slope Excavation

Abstract

Bedding cutting slopes are controlled by the occurrence conditions of rock formations. Under the coupling effect of excavation unloading and environmental factors, they are prone to delayed instability, which has become a core bottleneck in mountain transportation infrastructure construction. Aiming at the problems such as lack of systematic standards for pre-support discrimination, poor design adaptability, and fragmented processes, this paper takes typical highway slopes as samples. Through on-site investigation, laboratory tests, numerical simulation, and engineering verification, it analyzes the core influencing factors of stability, and identifies 6 types of typical failure modes and their evolution laws. A three-level classification system is constructed, and a four-step closed-loop pre-support process is innovatively proposed, clarifying the support selection and parameter design methods. Verified by numerical simulation and case studies, 6 types of slopes such as gently to moderately inclined soft rock slopes require key discrimination. The combined support of anchor (cable) and grouting has the widest adaptability, which can improve the slope safety factor and save costs. The research results provide theoretical support and technical solutions for the safety of bedding slopes, and are of great significance for disaster prevention and mitigation in mountain transportation infrastructure.