﻿ 文登地下厂房开挖方案围岩稳定性分析 Stability Analysis of Wendeng Underground Plant According to Excavation Schemes

Hans Journal of Civil Engineering
Vol.07 No.02(2018), Article ID:24206,11 pages
10.12677/HJCE.2018.72029

Stability Analysis of Wendeng Underground Plant According to Excavation Schemes

Chaoyue Wu1, Shaojun Fu2, Hailong Shang1, Shufa Wang3, Xiang Xi3, Changhai He3

2School of Civil Engineering, Xijing University, Xi’an Shaanxi

3School of Water Resources and Hydropower Engineering, Wuhan University, Wuhan Hubei

Received: Mar. 5th, 2018; accepted: Mar. 20th, 2018; published: Mar. 27th, 2018

ABSTRACT

Excavation procedure and selection of excavation method for the realization of rapid, economic and safety construction of underground plant are very important. This paper will take the underground plant of Wendeng pumped storage power station as an example, three excavation schemes are mapped out with the idea of “many processes in plane and 3-D multi-level”. The corresponding finite element model is established, the initial stress is inverted by GA, and the nonlinear finite element simulation is adopted to analyze the deformation, stress state and yield zone distribution of surrounding rock under different excavation schemes. The results showed that the overall stability of surrounding rock for the three excavation schemes is good, the local deformation and stability was mainly affected by the two major faults. The excavation implementation plan should be made and optimized according to the schedule requirements and construction conditions. The achievement of the study provides a basis for the construction scheme optimization of underground plant in Wendeng project, which also can be a reference for similar projects.

Keywords:Underground Plant, Excavation Scheme, Stability, Finite Element Analysis

1中国电建集团北京勘测设计研究院，北京

2西京学院，土木工程学院，陕西 西安

3武汉大学，水利水电学院，湖北 武汉

1. 引言

2. 工程概况及基本技术资料

2.1. 工程概况

2.2. 地质条件及参数

2.3. 开挖方案

Figure 1. Transverse section of underground plant

Table 1. The recommended value of mechanic parameter of joints and faults

3. 初始地应力反演

3.1. 实测地应力

3.2. 反演方法

Table 2. The recommended value of mechanic parameter of surrounding rock

Figure 2. The conventional excavation plan

Figure 3. The Three-dimensional excavation plan 1

Figure 4. The Three-dimensional excavation plan 2

$\sigma =f\left(x,y,z,E,\mu ,\gamma ,\Delta ,U,V,W,T\cdots \right)$ (1)

Figure 5. The boundary modes

$\phi =\sum _{i=1}^{n}|{\sigma }_{i}-{{\sigma }^{\prime }}_{i}|$ (2)

3.3. 反演结果

4. 围岩稳定数值分析

4.1. 有限元模型

1) 有限元网格模型

2) 力学模型

${\left\{\Delta \sigma \right\}}^{n}={\left[\stackrel{^}{D}\right]}^{n}\left({\left\{\Delta \epsilon \right\}}^{n}-{\left\{{\epsilon }^{\nu p}\right\}}^{n}\Delta t{}_{n}\right)$ (3)

4.2. 计算结果分析

4.2.1. 位移结果分析

Figure 6. The finite element mesh

Figure 7. The displacement vector induced by excavation on 1# electrical wire hall section

Figure 8. The displacement vector induced by excavation on longitudinal section of main power house

4.2.2. 应力结果

Table 4. Deformation of specific points (unit: mm)

Figure 9. Contour of σ3 on 3# electrical wire hall section

Figure 10. Contour of σ1 on 3# electrical wire hall section

4.2.3. 屈服区

4.3. 关键开挖步分析

1) 开挖第三层岩体

Figure 11. Yield zone on 1# electrical wire hall section

Figure 12. Yield zone on 3# electrical wire hall section

Figure 13. Yield zone on longitudinal section of main power house

2) 开挖第四层岩体

Figure 14. The displacement vector induced by excavation on 3# electrical wire hall section

Figure 15. Yield zone on 3# electrical wire hall section

Figure 16. The displacement vector induced by excavation on 3# electrical wire hall section

Figure 17. Yield zone on 3# electrical wire hall section

5. 结论

1) 根据实测应力值，反演了厂区的初始地应力场，该区属于中等地应力水平，反演结果合理。

2) 根据拟定的洞室群开挖施工方案，从变形、应力分布及屈服区情况对比了三个开挖方案。结果表明：

a) 由于地下厂房布置在I类围岩内，且岩体条件总体较好，因此三个开挖方案在变形、应力分布及屈服区等指标方面差异不大，以弹性变形为主，整体围岩稳定，局部的变形和应力主要受f202和f203断层的影响。

b) 立体开挖方案1、立体开挖方案2的洞周变形与常规开挖方案的洞周变形相差小于1 mm。

c) 洞周围岩总体处于受压状态，在洞周部分断层出露处和洞室底板局部出现受拉区域，最大拉应力小于2.0 MPa，主压应力小于20 MPa。

d) 屈服区主要分布在主洞室与母线洞交叉部分及受开挖影响的断层区域内，洞周围岩局部最大屈服区深度均小于4 m。

e) 应在主洞室与母线洞交叉等部位围岩加强支护。

3) 常规开挖方案与拟订的两个立体开挖方案在施工过程中围岩整体均稳定，仅从围岩稳定的角度来看是可行的。因此，在制定开挖实施方案时可根据进度要求、施工条件等优化开挖步序。

Stability Analysis of Wendeng Underground Plant According to Excavation Schemes[J]. 土木工程, 2018, 07(02): 244-254. https://doi.org/10.12677/HJCE.2018.72029

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