﻿ 乌市地铁1号线盾构隧道近接既有建筑的施工力学特性分析 Analysis of Construction Mechanics Characteristics of Existing Shield Tunnels in Wuzhou Metro Line 1

Hans Journal of Civil Engineering
Vol. 08  No. 10 ( 2019 ), Article ID: 33459 , 8 pages
10.12677/HJCE.2019.810166

Analysis of Construction Mechanics Characteristics of Existing Shield Tunnels in Wuzhou Metro Line 1

Ren Tang

Xinjiang Wujing Infrastructure Construction Management Co. Ltd., Urumqi Xinjiang

Received: Nov. 13th, 2019; accepted: Dec. 9th, 2019; published: Dec. 16th, 2019

ABSTRACT

The tunneling construction of shielded tunnels adjacent to existing buildings has many uncertainties and difficult deformation control. In order to analyze the construction mechanical properties of the shield adjacent to existing buildings, a three-dimensional model of shield tunnel, stratum and adjacent existing buildings was established. The large-scale geotechnical software FLAC3D was used to simulate the whole process of the adjacent construction. The numerical analysis results show that after the completion of the left and right lines of the shield, the maximum settlement of the ground is about 4.51 mm, and the influence of the ground subsidence is within 24.5 m of the center line of the tunnel. The settlement of the soil around the lining structure is about 15.5 - 16.6 mm. In order to control the soil loss of the surrounding rock of the tunnel, it is necessary to strengthen the construction measures such as shield tail grouting and secondary grouting. The research results can provide a reference for the construction of shielded adjacent buildings in the similar geological environment of Urumqi.

Keywords:Subway Tunnel, Construction Control, Shield, Numerical Simulation

1. 引言

2. 工程概况

Figure 1. Building plan

Figure 2. Location relationship between a quality monitoring center building and the subway

Figure 3. Model plane dimensions

3. 地层结构

4. 三维模型及计算参数

4.1. 模型建立

Figure 4. Tunnel and proximity building model

Figure 5. Model meshing tunnel

4.2. 计算参数及边界条件

Table 1. Numerical calculation parameters

4.3. 计算的本构模型和屈服准则

5. 盾构隧道近接某质量监控中心大楼的施工力学特性

5.1. 计算工况

① 右线隧道开挖面距离某质量监中心大楼10 m；

② 右线隧道开挖面距离某质量监中心大楼5 m；

③ 右线隧道穿越某质量监中心大楼的中心；

④ 右线隧道穿越某质量监中心大楼；

⑤ 右线隧道已完全穿越模型且左线开挖至距离某质量监中心大楼10 m；

⑥ 右线隧道已完全穿越模型且左线开挖至距离某质量监中心大楼5 m；

⑦ 左线隧道已完全穿越某质量监中心大楼。

5.2. 开挖及衬砌结构模拟

① 盾构掘进的数值实现

② 衬砌结构的模拟

Figure 6. Lining structure and simultaneous grouting calculation model

5.3. 盾构隧道近接某质量监控中心大楼的施工计算结果

Table 2. Construction mechanical properties of shield tunnels in each condition

①地面沉降

Figure 7. Contour map of the ground subsidence when the right line and the left line are completely close to the flight building/m

Figure 8. The right and left lines are completely close to the tunnel center ground monitoring point when crossing the flight building/m

Figure 9. Contour map of lining settlement when the left and right lines pass through the building/m

Figure 10. The maximum principal stress of the shield lining when the left and right lines pass through the building/Pa

Figure 11. Maximum small principal stress of shield lining when the left and right lines pass through the building/Pa

6. 结论和建议

① 盾构隧道在穿越质量监控中心大楼的过程中，随着开挖断面越来越靠近大楼基础，其地面沉降、基础位移以及沉降结构应力逐渐变大。

② 盾构开挖完成后，沉降区域为漏斗型，影响范围为中心线左右24.4 m，最大沉降为4.51 mm，但沉降最大地方并非在盾构轴线地面处。

③ 1号线土压平衡盾构机的盾尾与周围土体存在1 cm的盾尾间隙，土体开挖后，壁后土体沉降较大，最大沉降约为15.5~16.6 mm，为控制围岩沉降和地面沉降值，应加强盾尾注浆及地面注浆。

④ 衬砌结构的最大主应力约为−0.41 MPa，最小主应力约为−3.7~−3.8 MPa (表示压力)，随着开挖工况的进行，其值变化不大，总体受力满足衬砌结构的强度要求。

⑤ 为确保盾构穿越民建房屋时的安全，需在盾构推进过程中，加强监控频率，优化掘进参数，保证后注浆质量，以此来控制地面沉降。

Analysis of Construction Mechanics Characteristics of Existing Shield Tunnels in Wuzhou Metro Line 1[J]. 土木工程, 2019, 08(10): 1423-1430. https://doi.org/10.12677/HJCE.2019.810166

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