隧道爆破对邻近桩基稳定性影响研究

发布时间：2018-08-20 13:21

【摘要】：采用钻爆法开挖隧道对周边建(构)筑物所产生的震动效应是一个值得关注的问题。本文以重庆市轨道交通环线二期奥陈区间隧道工程为依托,结合现场监测数据,运用ANSYS/LS-DYNA动力分析软件进行数值模拟分析,分析城市浅埋隧道爆破对邻近桩基稳定性的影响,通过计算分析得到以下结论:(1)通过数值模拟计算得出桩基距离隧道开挖边界10m范围内峰值震动速度大、衰减快,在该区域桩基峰值振动速度大于3.5cm/s,超过安全标准值,针对奥陈区间类似浅埋隧道工程,在隧道选址过程中应确保桩基距离隧道的水平距离在10m范围外,对于桩基距离隧道水平距离小于10m的工程应尽量采用非爆破开挖方法,采用爆破开挖方式时,掘进进尺应控制在1m范围内。(2)通过对比分析桩基x、y、z方向峰值震动速度及峰值合速度变化规律得出:总体上,y方向的峰值振动速度变化规律与振动合速度变化规律相似,说明桩基y方向的振动速度与合速度拟合较好,若以合速度分量作为评估桩基安全指标应采用y方向的峰值振动速度。(3)为控制隧道爆破对邻近桩基的震动影响应选择合适的爆破掘进尺度,针对重庆地区奥陈类似隧道工程,当爆破进尺为1m时,桩基与隧道开挖边界线的安全水平距离是12m;当爆破进尺为1.5m时,桩基与隧道开挖边界线的安全水平距离是15m;当爆破进尺为2m时,桩基与隧道开挖边界线的安全水平距离是18m;当爆破进尺为2.5m时,桩基与隧道开挖边界线的安全水平距离是25m。(4)通过对奥陈隧道爆破过程中邻近龙井湾大桥桩基的振动速度监测,得出桩基垂直方向振动速度最大,桩基距离爆源最小水平距离为23m,测得垂直方向爆破振动速度为2.59cm/s,未超过桩基爆破振动规定安全值,在该工况下,工程采用的爆破方案不会对桩基造成危害。
[Abstract]:The vibration effect of tunnel excavation by drilling and blasting is a problem worth paying attention to. In this paper, based on the tunnel project of Orchan section in the second phase of Chongqing rail transit ring line, combined with field monitoring data, numerical simulation analysis is carried out by using ANSYS/LS-DYNA dynamic analysis software, and the influence of blasting on the stability of adjacent pile foundation is analyzed. The main conclusions are as follows: (1) through numerical simulation, the peak vibration velocity is large and attenuation is fast in the range of 10m from the tunnel excavation boundary. The peak vibration velocity of pile foundation is more than 3.5 cm / s in this area, which exceeds the safe standard value. In view of the similar shallow tunnel engineering in Orchan interval, the horizontal distance between pile foundation and tunnel should be in the range of 10m in the course of tunnel location selection, and the non-blasting excavation method should be used as far as possible for those projects where the horizontal distance between pile foundation and tunnel is less than 10m. When blasting excavation is adopted, The driving ruler should be controlled within 1 m. (2) by comparing and analyzing the variation law of the peak vibration velocity and the peak velocity in the direction of pile foundation, it is concluded that the variation law of the peak vibration velocity in the overall direction of y is similar to the law of the change of the velocity of vibration combination. It shows that the vibration velocity of the pile foundation in the y direction fits well with the closing velocity. If the combined velocity component is used as the evaluation index of pile foundation safety, the peak vibration velocity in y direction should be adopted. (3) in order to control the vibration effect of tunnel blasting on adjacent pile foundation, the appropriate blasting excavation scale should be selected, and aiming at the similar tunnel project in Chongqing area, When the blasting scale is 1 m, the safe horizontal distance between the pile foundation and the tunnel excavation boundary is 12 m, when the blasting scale is 1.5 m, the safe horizontal distance between the pile foundation and the tunnel excavation boundary is 15 m, and when the blasting scale is 2 m, the safe horizontal distance between the pile foundation and the tunnel excavation boundary is 15 m. The safe horizontal distance between the pile foundation and the tunnel excavation boundary is 18 m, and the safe horizontal distance between the pile foundation and the tunnel excavation boundary is 25 m when the blasting scale is 2.5 m. (4) the vibration velocity of the pile foundation adjacent to Longjing Bay Bridge during the blasting process of the Orchan Tunnel is monitored. The maximum vertical vibration velocity of pile foundation is obtained, the minimum horizontal distance between pile foundation and explosion source is 23m, and the vertical blasting vibration velocity is 2.59 cm / s, which does not exceed the specified safety value of pile foundation blasting vibration. The blasting scheme adopted in the project will not cause harm to the pile foundation.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.6;TU473.1

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