摘要
滇中引水隧洞工程致灾地质体复杂多样,极大增加超前探测结果解译难度。为此,基于致灾地质体分布特征和电性参数特征,分别建立充填不同介质的溶洞、含水体及软岩3种典型致灾地质体理论模型,采用时域有限差分正演和基于S变换改进的广义S变换,开展雷达波场数值模拟和时-频特性研究。雷达波场特征为:溶洞顶界面出现弧形反射,且充水溶洞振幅能量强于充气溶洞振幅能量;在含水体发育区域,出现多条水平状强振幅反射同相轴;在软岩发育区域,软岩顶、底界面呈水平强振幅反射;含水溶洞、含水体及软岩的顶界面反射波均会出现相位反转现象。雷达信号时-频特性为:当信号经过溶洞和含水体发育区域时,其中心频率集中在某一低频范围内;当信号经过软岩发育区域时,其中心频率分布较为分散,在高频和低频区间均有分布。依据滇中引水工程4个成功探测实例,通过分析雷达实测信号的波场、时-频分布、单道信号和功率谱衰减特征,与其相应数值模拟结果特征基本一致,证实数值模拟结果的可靠性。研究结果为隧洞典型致灾地质体探测、特征识别与防治处理提供了科学依据,具有重要理论意义和工程应用价值。
The complexity and variety of disaster-causing geologic bodies in the tunnel of the Central Yunnan Water Diversion Project greatly increase the difficulty of interpreting the results of advanced detection.For this reason,based on the distribution characteristics and electrical parameters of the disaster-causing geological bodies,this paper establishes the theoretical models of three typical disaster-causing geological bodies,namely,caves filled with different media,water bodies,and soft-rocks,and then carries out the numerical simulation of the ground penetrating radar wave field and the research of time-frequency characteristics by adopting time-domain finite-difference forward modeling and the generalized S-transform improved based on S-transform.The groundpenetrating-radar wave-field is characterized by the following:arc-shaped reflection at the top interface of the karst cave,and the amplitude energy of water-filled karst cave is stronger than the air-filled karst cave;in the area of the water-bearing,there are several horizontal strong amplitude reflection events;in the area of the soft-rock,there are horizontal strong amplitude reflections on the interface of the soft-rock top and bottom;and the reflected waves from the top interfaces of water-filled caves,water-bearing bodies,and soft-rocks will have the phenomenon of phase reversal.The time-frequency characteristics of the ground penetrating radar signal are as follows:when the signal passes through the areas of the karst caves and water-bearing,its central frequency is concentrated in a lowfrequency range;When the signal passes through the area of the soft-rocks,its central frequency distribution is more dispersed,and it is distributed in both high-frequency and low-frequency range.Based on four successful detection cases of the Central Yunnan Water Diversion Project,the wave-field,time-frequency distribution,singletrace signal,and power spectrum attenuation characteristics of ground penetrating radar real signals are consistent with their corresponding numerical simulation results,which confirms the reliability of numerical simulation results.The results of the study provide a scientific basis for the detection,feature identification,and prevention of typical disaster-causing geological bodies in tunnels,which is of great theoretical significance and engineering application value.
作者
周黎明
张杨
付代光
夏波
ZHOU Liming;ZHANG Yang;FU Daiguang;XIA Bo(Key Laboratory of Geotechnical Mechanics and Engineering of the Ministry of Water Resources,Changjiang River Scientific Research Institute,Wuhan,Hubei 430010,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2024年第S02期3668-3680,共13页
Chinese Journal of Rock Mechanics and Engineering
基金
中央级公益性科研院所基本科研业务费项目(CKSF2023316/YT,CKSF2024345/YT)
关键词
隧道工程
隧洞超前探测
GPR
典型致灾地质体
数值模拟
时-频分析
功率谱衰减
tunnel engineering
tunnel advance forecast
ground penetrating radar
typical geological bodies causing disasters
numerical simulation
time-frequency analysis
power spectrum attenuation
作者简介
周黎明(1977-),男,博士,2003年毕业于中国地质大学(武汉)地球探测与信息技术专业,现任正高级工程师,主要从事岩土工程地球物理方面的研究工作。E-mail:zhouliming@mail.crsri.cn
