﻿ 新坝基础开挖爆破对老坝安全影响的动力分析 Dynamic Analysis of Influence of New Dam Foundation Excavation Blasting on Safety of Old Dam

Hans Journal of Civil Engineering
Vol.07 No.03(2018), Article ID:24799,8 pages
10.12677/HJCE.2018.73037

Dynamic Analysis of Influence of New Dam Foundation Excavation Blasting on Safety of Old Dam

Feng Liu1,2

1China Water Northeastern Investigation, Design & Research Co., Ltd., Changchun Jilin

2Research Center on Cold Region Engineering Ministry of Water Resources, Changchun Jilin

Received: Apr. 17th, 2018; accepted: May 1st, 2018; published: May 9th, 2018

ABSTRACT

According to the design data of excavation blasting of new dam foundation proposed, the shock wave generated by the blasting is determined according to the experimental data and the empirical formula of other engineering blasting. The dynamic finite element method (LS-DYNA) is used to simulate the old dam’s 3 longitudinal seams, and vibration speed, deformation and stress of important parts of the old dam caused by blasting are analyzed and evaluated. Under the new dam foundation’s excavation and blasting, the calculation results show: 1) the maximum single shot dose of excavation blasting of the new dam foundation proposed can meet safety requirements; 2) the stress of the old dam body is small and can meet requirement of the specification; 3) it is appropriate to allow the vibration velocity to be 3.0 cm/s.

Keywords:New Dam Foundation, Excavation Blasting, Old Dam, Dynamic Analysis

1中水东北勘测设计研究有限责任公司，吉林 长春

2水利部寒区工程技术研究中心，吉林 长春

1. 引言

2. 工程概况

3. 爆破振动荷载及安全控制标准

3.1. 爆破振动荷载

$V=K{\left(\frac{{Q}^{1/3}}{R}\right)}^{\alpha }$ (1)

3.2. 爆破振动安全控制标准

4. 数值计算及结果分析

4.1. 模型建立

4.2. 计算结果分析

4.2.1 . 振速分析

Figure 1. Blasting vibration wave monitored at project site

Figure 2. Finite element grid of No. 17 overflow section

Table 1. Allowable standard of blasting vibration for excavation of the new dam foundation (cm/s)

4.2.2. 变形分析

Figure 3. Dam’s vibration velocity distribution at blasting time 0.67 s (unit: m/s)

Figure 4. Dam’s vertical velocity distribution at blasting time 0.57 s (unit: m/s)

Figure 5. Dam’s horizontal displacement distribution at blasting time 0.67 s (unit: m)

Figure 6. Dam’s vertical displacement distribution at blasting time 0.67 s (unit: m)

4.2.3. 应力分析

4.2.4. 统计分析

Figure 7. Dam’s first principal stress distribution at blasting time 0.67 s (unit: m)

Figure 8. Dam’s third principal stress distribution at blasting time 0.67 s (unit: m)

Table 2. Summary of old dam’s maximum vibration caused by new dam foundation’s excavation blasting (cm/s)

Table 3. Summary of old dam longitudinal seams’ maximum effects caused by new dam foundation’s excavation blasting

1) 坝体关键部位的振速最大值在0.33 cm/s~3.06 cm/s之间，坝顶、坝址及纵缝部位相对较大，最大振速(3.06 cm/s)出现于溢流坝段的坝顶。

2) 坝体纵缝水平振速最大值在1.66 cm/s~2.66 cm/s之间，最大振速(2.66 cm/s)出现于溢流坝段；垂直振速最大值在1.27 cm/s~2.91 cm/s之间，最大振速(2.91 cm/s)亦出现于溢流坝段；水平与垂直振速最大值比较接近。

3) 坝体纵缝开度最大值在0.08 mm~0.30 mm之间，最大开度(0.30 mm)出现于溢流坝段；错动变形最大值在0.05 mm~0.19 mm之间，最大错动(0.19 mm)亦出现于溢流坝段。

4) 坝体纵缝拉应力最大值在0.23 MPa~0.31 MPa之间，最大拉应力(0.31 MPa)出现于溢流坝段；压应力最大值在0.18 MPa~0.33 MPa之间，最大压应力(0.33 MPa)出现于厂房坝段；拉应力与压应力最大值比较接近。

5. 结论

1) 坝体关键部位的振速均低于安全控制标准，拟定的新坝基础开挖爆破最大单响药量能够满足工程爆破安全要求。

2) 坝体最大变形多出现于坝顶和坝址，总体来讲，坝体变形均较小，属于对爆破的正常响应。

3) 坝体第一主应力均为拉应力，第三主应力均为压应力，坝体应力总体不大，能满足规范要求。

4) 坝体纵缝的振速、变形及应力均不大，均属于对爆破的正常响应；老坝坝体纵缝安全允许振速取为3.0 cm/s是合适的。

Dynamic Analysis of Influence of New Dam Foundation Excavation Blasting on Safety of Old Dam[J]. 土木工程, 2018, 07(03): 321-328. https://doi.org/10.12677/HJCE.2018.73037

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