干冰粉热冲击破岩基坑围护结构振动安全研究  

Vibration Safety of Foundation Pit Enclosure Structure with Thermal Impact Rock Breaking by Dry Ice Powder

作　　者：王小飞 胡少斌 王恩元[1] 黄俊 颜正勇 WANG Xiao-fei;HU Shao-bin;WANG En-yuan;HUANG Jun;YAN Zheng-yong(School of Safety Engineering,China University of Mining and Technology,Xuzhou 221116,Jiangsu,China;School of Civil and Transportation Engineering,Hohai University,Nanjing 210098,Jiangsu,China;JSTI Group Co.Ltd.,Nanjing 210019,Jiangsu,China)

机构地区：[1]中国矿业大学安全工程学院,江苏徐州221116 [2]河海大学土木与交通工程学院,江苏南京210098 [3]苏交科集团股份有限公司,江苏南京210019

出　　处：《中国公路学报》2024年第3期371-381,共11页China Journal of Highway and Transport

基　　金：国家自然科学基金-国家重大科研仪器研制项目(52227901);国家自然科学基金重点项目(51934007);山东省重大科技创新计划项目(2019JZZY020505);江苏省自然科学基金项目(BK20201313);住房与城乡建设部科技计划项目(2021-K-087)。

摘　　要：为了给干冰粉热冲击破岩现场设定施工参数设计提供参考,并对关键工程结构进行全面的安全评价,首次在居民区附近明挖隧道中进行了隧道开挖工程干冰粉热冲击破岩现场试验。在试验中通过压力传感器获得干冰粉致裂筒内部压力变化曲线,使用振动和噪音监测系统监测破岩过程中隧道结构的噪音和振动响应。通过希尔伯特黄变换对振动信号进行分解和特征提取,通过振动能量时域分布和频域分布特征获得振动安全评价参数。研究结果表明:(1)干冰气动破岩最大振动速度在砼冠梁8 m处衰减至50 mm·s^(-1)以下,满足安全质点振动速度要求,噪音在4 m处仅为83 dB,对周边居民生活影响很小;(2)干冰破岩诱发振动速度整体上呈衰减趋势,且符合乘幂函数衰减,可以划分为振动速度缓慢降低区(2.5~10 m)和稳定区(>10 m)两个区域;(3)干冰粉致裂管破裂压力在40~60 MPa,干冰粉热冲击破岩是冲击波和高能气体共同作用致裂岩石,可以分为3个阶段,其中高能气体的气楔作用在岩体损伤中占主导作用;(4)HHT与傅里叶变换分析相比更适用于处理振动信号,获得振动速度峰值和主频率后计算振动最大位移可以更好地对隧道结构进行安全评估。干冰粉热冲击破岩是一种比传统钻爆法更加安全的破岩技术,振动弱,噪音小,适合在城市敏感区域应用。This study aimed to establish construction parameters for on-site use of dry ice powder thermal shock breaking and conduct a comprehensive safety evaluation of critical engineering structures.The first field test of dry ice powder thermal shock rock-breaking for tunnel excavation was conducted in an open-cut tunnel near a residential area.Pressure variation curves were captured from the dry ice powder fracturing cylinder using pressure sensors.Concurrently,the tunnel structure's noise and vibration responses during the breaking process were monitored using specialized systems.The Hilbert Huang transform(HHT)was used to decompose and extract features from the vibration signal,and the vibration safety evaluation parameters were determined from the vibration energy time-domain distribution and frequency-domain distribution features.Results show that:①the maximum vibration speed of dry ice pneumatic rock breaking reduces to less than 50mm·s^(-1) at a distance of 8mfrom the crown beam,complying with safe mass vibration speed requirements.Additionally,the noise level at a distance of 4mis 83dB,posing minimal impact on the life of nearby residents;②overall,the vibration speed induced by dry ice rock breaking decays in alignment with the multiplicative power function decay.This decay can be categorized into a zone of slowly decreasing vibration speed(2.5-10m)and a stable zone(>10m);③the rupture pressure of the dry ice powder fracture tube ranges between 40-60 MPa.Dry ice powder thermal shock rock breaking is a collective action of a shock wave and high-energy gas,which fractures the rock and occurs in three stages.The gas wedge of high-energy gas plays a key role in causing rock damage;④compared to Fourier transform analysis,the HHT is better suited for processing vibration signals.By calculating the vibration's maximum displacement after identifying the vibration velocity peak and main frequency,the safety of the tunnel structure can be more effectively assessed.

关 键 词：隧道工程 干冰粉热冲击破岩 振动安全 希尔伯特黄变换 

分 类 号：U458.2[建筑科学—桥梁与隧道工程]