公路隧道岩质和土质围岩统一亚级分级标准研究

Study of unified standard of rocky and soil surrounding rock sub-classification in road tunnels

目前实施的《公路隧道设计规范》(JTGD70-2004)对土质围岩分级、围岩亚级分级方法都没有进行研究,因此,不能满足隧道设计和施工的要求。通过对岩质围岩和土质围岩自稳性的大量室内试验、数值计算和理论分析,建立了公路隧道岩质围岩和土质围岩统一的亚级分级标准。研究结果显示:围岩自稳跨度是围岩自稳性的综合反映,围岩自稳跨度可分为长期稳定跨度、基本稳定跨度、暂时稳定跨度和不稳定跨度。研究表明,规范中岩质围岩的Ⅲ级、Ⅳ级和Ⅴ级分别依据自稳跨度可分为2个、3个和2个亚级;土质围岩尽管分为黏质土围岩、砂质土围岩及碎石土围岩,但按照各自的自稳跨度可以分别进行亚级划分。可见,以自稳跨度可以建立岩质围岩和土质围岩统一的亚级分级标准。

The implementary Code for Design of Road Tunnel （JTG D70--2004） can＇t satisfy the requirement of design and construction sometimes due to no study of soil surrounding rock classification and sub-classification methods. After ascertaining the building foundation of surrounding rock sub-classification standard in road tunnel, it had been constituted through lots of test, numerical calculation and theoretical analysis. The researches show that self-stability span is synthetical reflection of surrounding rock stability, so sub-classification standard can be constituted based on it. Surrounding rock self-stability span can divide into long-term stability span, basic stability span, temporary stability span and instability span. Ⅲ class of Rocky surrounding rock in criterion can divide into two sub-classification according as surrounding rock stability, three for Ⅳ class and two for Ⅴ class. Though soil surrounding rock include clayey surrounding rock, sandy surrounding rock and debris surrounding rock, their stability can be unified. The uniform standard of rocky and soil surrounding rock sub-classification built by self-stability span has rationality and inheritance.