摘要
研究目的:现有隧道初期支护的设计方法主要有工程类比法、地层结构法、特征曲线法等,这些方法在实际工程应用中均存在一定的局限性和困难,且没有提出明确的安全系数要求,导致设计的可靠性降低,不便于设计应用,因此有必要研究便于量化设计并具有明确安全系数的荷载结构法。研究结论:(1)本文所建立的初期支护荷载结构模型,可以得出初期支护的具体安全系数;(2)在锚杆长度满足模型三所需安全系数的前提下,喷锚组合支护的安全系数由喷层和锚杆各自的安全系数相加而成;(3)初期支护的最小安全系数取值需要根据计算模型的计算精度、初期支护的设计作用以及隧道工程的特点等因素综合确定,建议初期支护作为承载主体时为1.8～2.1,作为临时支护时为1.3～1.5;(4)现行时速350 km高速铁路双线隧道深埋Ⅲ、Ⅳ级围岩支护参数的安全性计算结果表明,当初期支护作为承载主体时,Ⅲ级围岩支护参数具有一定的优化余地,Ⅳ级围岩支护参数能适应400 m以内埋深;当初期支护仅作为临时承载结构时,Ⅳ级围岩支护参数能适应1 000 m以内埋深;(5)隧道埋深对围岩压力影响较大,建议按照不同埋深进行初期支护设计,以提高经济性;(6)本研究结果可为隧道初期支护设计提供思路和方法。
Research purposes： The current design methods of primary support of tunnel are engineering analogy,layer structure method,characteristic curve method,etc. These methods have some limitations and difficulties in practical engineering applications,and there are no specific requirements for safety factors,which leads to the reduction of design reliability and the inconvenience for design. It is necessary to study the design method based on the load structure method which is easy to quantify and has clear safety factor.Research conclusions：(1） The load structure model established for primary support in this paper can get the specific safety factor.(2） The safety factor of combined support of shotcrete and anchor is summed by the respective safety factors of shotcrete and anchor under the premise that the anchor length meets the safety coefficient of the model three.(3） The minimum value of safety factor for primary support needs to be determined comprehensively according to the calculation accuracy of the load-structure model,the design of primary support and the characteristics of tunnel engineering. It is suggested that when the primary support is taken as the main bearing structure,it is 1. 8 ～ 2. 1,and it is 1. 3 ～ 1. 5 as a temporary support.(4） The safety calculation results for the parameters of the current speed of 350 km high-speed railway double line tunnel deep-buried in surrounding rock of Ⅲ and Ⅳ show that when the primarysupport is used as the main bearing structure,the primary support parameters for surrounding rock Ⅲhave a certain level of optimization,the support parameters for surrounding rockⅣcan adapt within 400 m depth. When the primary support is only used as the temporary bearing structure,the primary support parameters for surrounding rockⅣcan adapt to the depth of 1 000 m.(5） The buried depth of the tunnel has a great influence on the surrounding rock pressure. It is suggested that the primary support design should be conducted according to different buried depth i
作者
肖明清
王少锋
陈立保
徐晨
XIAO Ming - qing;WANG Shao - feng;CHEN Li - bao;XU Chen(China Railway Siyuan Survey and Design Group Co. Ltd, Wuhan, Hubei 430063 ,Chin)
出处
《铁道工程学报》
EI
北大核心
2018年第4期60-64,共5页
Journal of Railway Engineering Society
关键词
初期支护
设计方法
荷载结构法
安全系数法
primary support
design method
load-structure method
general safety factor method
