摘 要

随着我国经济的不停提升以及城市化的加速，现有的公路及铁路交通己经远远不及满足日渐增加的运输需求。在隧道修建过程中不可避免的会出现穿越山岭的情况，尤其是在我国西南、西北等部分多山地区，穿山隧道的修建成为这些地方交通线路不可或缺的重要组成部分。在我国早些的公路隧道建设中，因为隧道数目相对较少、用地较多、经济欠发达和隧道施工技术不成熟等多方面的因素，公路隧道一般设计成为分离式独立双洞隧道。然而交通量的日益加，我国的隧道工程也在随着逐年递增。相对于早期的隧道建设，而今隧道隧址的选择性越来越受到土地与环境等多方面条件的约束和限制。特别是现在城市之间各类管线、路线和其周边建筑物繁多，隧道设计时为了兼顾思量对周边临近建(构)筑物的影响，展线越来越艰难。所以，为了顺应这种形势的需求，往往将新建隧道与隧道之间间距设计的越来越小，如此便诞生了一种新的隧道结构形势:小净距隧道。

小净距隧道布置灵活，对地形适应性较强，且施工工艺，工程造价较连拱隧道简单，为此，在我国公路隧道建设中小净距隧道应用越来越广泛。

小净距隧道也有其自身局限性，依然有许多技术性问题急待解决，设计标准和破坏准则急待完善。尤其是后行洞钻爆掘进施工时会对先行洞初支产生一定的影响，如果爆破控制不当，则促进围岩裂隙快速发育，围岩稳定性受到很大影响；造成已完工的衬砌也会产生裂缝等一系列问题。

论文主要依托长岭隧道工程，在不同的围岩情况下，对隧道爆破掘进施工方法与小净距隧道爆破掘进施工方法的研究，论文主要内容和取得成果如下：

（1）查阅长岭隧道地质资料，施工图设计图纸，取得该隧道工程资料。

（2）简单阐述了岩土爆破的主要特征，简要介绍了影响岩土爆破效果的主要因素，同时对工程中常见的隧道掘进爆破方案进行阐述，此中主要包含全断面法、台阶法等开挖工况。

（3）分析小净距隧道开挖的特点，对三台阶预留核心土开挖工法进行了方案必选、参数设计。

（4）使用大型有限元分析软件，对三台阶预留核心土开挖工法进行了模式计算，得出了合理的台阶长度等一系列的优化参数。

关键词：小净距隧道，数值模拟，台阶法

Abstract

With the continuous development of China's economy and the accelerated pace of urbanization, the existing road traffic has been far from enough to meet the growing demand for transport. In the tunnel construction inevitably in the process will be across the mountains, especially in the southwest and northwest part of China's mountainous area, on the construction of the tunnel Chuanshan became an important part indispensable to where the traffic lines. In the early stage of our country in the construction of highway tunnel, due to the relatively small number of tunnel, more land, economic less developed and tunnel construction technology is not mature in many aspects, such as, road tunnel design become separated double tunnel. However, with the increasing traffic volume, the tunnel project in our country is increasing year by year. Compared with the early construction of the tunnel, the selectivity of the tunnel site is more and more restricted by the land, environment and other conditions. Especially in the modern city, a variety of pipelines, roads and other buildings are numerous, the tunnel design in order to take into account the impact on the surrounding construction (construction), the development of the line is becoming more and more difficult. Therefore, in order to adapt to the demand of this situation, the design of the space between the new tunnel and the tunnel is more and more small, so that a new type of tunnel structure is derived.

Small spacing tunnel layout flexibility, strong adaptability to the terrain, and the construction process, the project cost more than even the arch tunnel is simple, for this, in our country highway tunnel construction of small and medium-sized tunnel application more and more extensive.

Small clear distance tunnel also has its own limitations, there are still many technical problems to be solved, the design criteria and failure criteria to be improved. Especially underwent hole drilling and blasting excavation construction will be the first hole at the beginning of a certain effect, if the improper control of blasting, promote the fast growth of the fractured surrounding rock, surrounding rock stability have great influence on; cause has been completed the lining will produce crack and a series of problems.

This paper mainly rely on the Changling tunnel project, under different surrounding rock conditions, the research on the construction method of tunnel blasting excavation and the construction method of blasting excavation of small spacing tunnel, the main contents and achievements are as follows:

(1) access to the Changling tunnel geological data, construction drawings, design drawings, and obtain the information of the tunnel project.

(2) briefly discusses the main characteristics of soil and rock blasting, main factors influence the effect of rock blasting are introduced briefly, and elaborate engineering common tunneling blasting scheme, including full section method, bench cut method, such as excavation conditions.

(3) analysis characteristics of small clear distance tunnel excavation, of three bench reservation core soil excavation method for the mandatory program, parameter design.

(4) using the large-scale finite element analysis software, of three bench reservation core soil excavation method for the mode calculation and reasonable step length and so on a series of optimized parameters are obtained.

Key words: small spacing tunnel, numerical simulation, step method

目录

中文摘要 I

Abstract II

第一章 绪论 1

1.1小净距隧道概念 1

1.2小净距隧道的国内外研究现状 1

1.3国内外爆破施工研究现状 2

1.4本文研究的主要内容、方法及意义 3

第二章 隧道爆破掘进方案 4

2.1全断面法 4

2.2台阶法开挖 4

2.3导坑法开挖 5

2.4CD法和CRD法 5

第三章 长岭隧道工程概况 6

3.1地形地貌 6

3.2地质构造 6

3.3水文地质条件 6

3.4岩土体工程地质特征 6

3.5洞身开挖施工工艺方案 7

3.6后行洞小净距Ⅴ级围岩开挖施工 8

3.7小净距Ⅳ级围岩开挖施工 8

3.8洞身开挖爆破方案 8

3.8.1三台阶预留核心土开挖法爆破设计 9

3.8.2爆破参数 10

3.8.33CD开挖法爆破设计 10

3.9Ⅳ级围岩两台阶爆破设计 13

第四章 小净距隧道的开挖方法 14

4.1I级围岩段 14

4.2II级围岩段 14

4.3III围岩段 14

4.4IV围岩段 15

4.5 V、VI围岩段_x 16

4.6总结 17

第五章 小净距隧道不同工法数值模拟 18

5.1 模型建立 18

5.2 三台阶工法结果分析 19

5.2.1初支沉降水平X向变形 19

5.2.2初支沉降XYZ向变形 20

5.2.3初支水平X向应力 21

5.2.4初支水平Y向应力 22

第六章 结论 25

参考文献 26

致 谢 28

第一章 绪论

随着我国经济的飞速发展，不同地区间的技术交流，劳动力转移，及生产技术资料的沟通交流越来越密切，为了缩短地区间到达时间，我国修建了大量公路、铁路，其中高速公路作为布置灵活、造价适中的交通运输代表，极大的促进了国家经济的发展和人民生活水平、生活品质的提升。按照国家交通部规划，我国高速公路总里程数已达到世界前列，这其中很大一部分集中在地幅辽阔，人数相对稀少的中西部地区。

我国中西部地区地形较为复杂，多山多水，以湖北为例，鄂西北地区高速公路桥隧占比较大，地质情况较差，隧道围岩多为Ⅳ、Ⅴ级，围岩超欠挖情况较为突出，另外，由于线路总体规划及工程造价等因素的综合影响，高速公路沿线所修筑的隧道受各种因素的影响，左右洞的间距可能较小，且有时往往不能够满足国家公路桥隧等相关规范设计的要求。