摘 要

深部岩体所处的复杂的地质环境，导致地应力高、温度高、渗透压高，加之较强的时间效应，导致深部岩体表现出较强的流变特性，因此，深部岩体的流变特性的分析与评价是影响隧道工程施工和运营的一块重要研究领域。

本文以宜巴高速公路峡口隧道工程为依托，首先利用试验研究峡口隧道的泥质灰岩的蠕的蠕变特性，发现其蠕变过程的三个阶段以及蠕变现象较为明显，在实际工程应用中需要特别考虑。然后利用ABAQUS有限元计算软件的岩体蠕变本构模型——扩展Drucke-Prager模型，对峡口隧道的设计进行了隧道开挖以及运营50年后的围岩的变形规律分析，获得了ZK107 300断面处的洞周位移值、洞周最大、小应力和竖向应力、洞周蠕变区以及衬砌塑性破坏区，进而分析评价了该断面处的隧道长期稳定性，避免高地应力软岩隧道在实际施工过程以及运营过程中出现衬砌开裂、衬砌下沉侵入二衬界限，甚至导致支护结构失稳、隧道塌方等灾害，从而有效避免重新设计施工所带来的经济损失以及时间成本的提高。

通过研究，本文认为：

（1）峡口隧道的泥质灰岩的蠕变在较低围压的作用下表现出衰减蠕变，在较高围压的作用下表现出稳定蠕变，甚至在围岩为60MPa时，试样出现加速蠕变的现象。在不同偏应力作用下，随着时间的增加，蠕变应变的变化情况并不相同，因此在考虑工程的长期稳定性时，必须对材料的蠕变特性给予高度重视。

（2）由于软岩的蠕变特性，在高地应力情况下的软岩隧洞会产生较明显的蠕变变形，通过利用ABAQUS对围岩稳定性的计算模拟，本文认为在峡口隧道工程中使用的二次衬砌 锚杆（索）的支护技术支护下，隧道在运行50年后的洞周允许洞周水平相对收敛值符合规范标准，同时衬砌几乎没有出现塑性破坏区，因此隧道设计满足长期稳定性的要求。

（3）由于流变特性的存在，随着隧洞的开挖，在衬砌刚刚施加的时候，围岩应力很大，拱脚处应力达到73.15MPa的压应力，随着时间的发展，围岩应力开始重分布，衬砌受力开始增加，围岩的应力开始减小，衬砌和围岩开始共同承受约为39MPa的压应力。同时，在隧道开挖支护的过程中，拱脚处围岩的出现应力集中现象，这将导致拱脚处的围岩和衬砌非常容易破坏，因此在实际施工过程中，拱脚处的变形与支护应特别关注。

关键词：高地应力；隧道；蠕变；数值模拟

Abstract

The complex geological environment of the deep rock mass gives birth to high ground stress, high temperature and high osmotic pressure. Together with strong time effect, this kind of environment results in strong rheological characteristics of the rock mass. Therefore, the analysis and evaluation of deep rock mass with rheological properties is an important researching field where it has a profound significance on the construction and operation of tunnel projects.

This paper takes Xiakou tunnel project of Yiba Expressway as a basement. Primarily, experiments were used to study the creep property of the argillaceous limestone in Xiakou tunnel. It was discovered that the three stages of the creep process and the creep phenomenon are obvious, which implied the necessity of special consideration in engineering applications. Secondly, the creep constitutive model of rock mass—the expansion of Drucke-Prager model in ABAQUS finite element calculation software was applied to analyze the deformation law of the surrounding rock of the design of tunnel at two time bases (respectively after the excavation and after 50 years’ function). The researcher obtained several vital statistics at the ZK107 300 section including the displacement around the hole, the maximum perforation around the hole, the small stress and vertical stress, the creep area around the hole, and the plastic failure zone of the lining. Continuously, assessment of the long-term stability of the tunnel at the section and avoided the high stress soft rock was worked out. It is helpful in avoiding the occurrence of the lining cracks, the lining sinks into the boundary of the second lining, and even the disasters such as the instability of the support structure and the collapse of the tunnel during the actual construction and operation, thus effectively reducing the potential economic loss and time cost caused by the redesigned construction.

Through the research, there lie three main points in this article:

1. The creep of the argillaceous limestone in the Xiakou tunnel exhibits attenuation creep under the effect of lower confining pressure, and exhibits stable creep under the effect of higher confining pressure, when the surrounding rock is 60MPa, the sample even appeared to accelerate the process of creep. Under different deviatoric stress, the change of creep strain is not the same with the increase of time. Therefore, when considering the long-term stability of the project, designers must pay great attention to creep characteristics of the material.

Due to the creep characteristics of soft rock, the soft rock tunnel under high ground stress will produce obvious creep deformation. By using ABAQUS to calculate the stability of surrounding rock, an assumption is raised in this article as follows: under the support of the secondary lining anchor(cable) support technology, the relative convergence value of the hole circumference of the tunnel after 50 years of operation will meet the specification standard. In addition, since there scarcely appears plastic damage zone in the lining, the tunnel design meets long-term stability requirements.

(3) Due to the existence of rheological properties, with the excavation of the tunnel, the surrounding rock stress is very large and the stress at the arch foot reaches a compressive stress of 73.15 MPa when the lining is just applied. As time goes, the stress of the surrounding rock starts to redistribution, the stress of the lining begins to increase, the stress of the surrounding rock begins to decrease, and the lining and surrounding rock begin to share a compressive stress of approximately 39 MPa. At the same time, in the process of tunnel excavation and support, stress concentration occurs in the surrounding rock of the arch foot, which will make the surrounding rock and lining at the arch foot extremely delicate. Therefore, the foot arch deformation and support shall be paid special attention in actual construction process.

Key Words：high ground stress; tunnel; creep; numerical simulation

目 录

第1章 绪论 1

1.1 论文的目的及意义 1

1.2 研究方法和研究思路 1

1.3 国内外的研究现状分析及本文研究内容 2

1.3.1 理论研究 2

1.3.2 理论解析法 2

1.3.3 数值模拟法 3

1.3.4 软岩长期稳定性领域存在的问题 3

1.3.5 本文的研究内容 3

第2章 峡口隧道工程概况及围岩蠕变特性试验研究 5

2.1 地形地貌 5

2.2 地质构造 5

2.3 地层岩性 5

2.4 峡口隧道围岩特性试验研究 6

2.4.1泥质灰岩常规特性 6

2.4.2泥质灰岩蠕变特性 6

第3章 峡口隧道长期稳定性分析 10

3.1 软岩流变的基本概念 10

3.2 ABAQUS软件介绍 10