摘要
针对自由面不仅影响爆破效果还影响爆破振动效应的问题,提出从能量角度探索自由面对水下爆破振动衰减规律的影响。以三峡大坝至葛洲坝水利枢纽河段水下钻孔爆破地震波现场监测数据为基础,结合SPH-FEM数值模拟技术和小波时频能量分析方法,对不同自由面数量的爆破振动信号的总能量、各频带间的能量分布特征及振动衰减规律进行了研究。结果表明:水下钻孔爆破具有低主频、短持时、快衰减的特点,爆破主频带主要集中在15.625~31.250 Hz;受单一自由面限制的水下开槽爆破,监测信号的爆炸能量主要以振动形式消耗,单自由面比振动能为13.14 mm^(2)/(kg·s^(2)),随着后续开挖爆破自由面数量的增加,双自由面和三自由面的比振动能分别降低至1.36和0.28 mm^(2)/(kg·s^(2)),频带质点峰值振动速度分别降低65%和37%,能量更多用于破碎和抛掷岩体,水下爆破振动主频由低频向高频带(31.25~62.50 Hz)发展。因此,在水下控制爆破设计时,需要考虑自由面数量对振动能量分布和衰减规律的影响,并利用这个特征,确定各段的控制药量,减少对周边建构物的共振危害。
Aiming at the problem that the free surface not only affected the blasting effect but also the blasting vibration effect,an analytical method of exploring the influence of free surface on the vibration attenuation law of underwater drilling blasting was proposed from the energy point of view.Taking the field monitoring data of the underwater blasting seismic wave between the river reach of the Three Gorges Dam and Gezhouba Dam as the research object,the characteristic information on time and frequency scales of the monitored signals was analyzed by wavelet transform.Similarly,the total energy of the blasting vibration signals,the energy distribution characteristics in variety of frequency band on different free surface,and the main frequency range were extracted.Combined with the method of the SPH-FEM simulation technology,the vibration velocity attenuation law of different numbers of free surfaces was verified.The results indicate that underwater drilling blasting vibration has the characteristic of low frequency,the short duration and the fast attenuation.The main frequency band of the underwater drilling blasting is focused on the frequency band of 15.625−31.250 Hz.Most of the explosion energy will be consumed as seismic energy in the underwater slotted blasting due to the restricted of a single free surface.The specific vibrational energy λ_(g) of the single free surface signal is 13.14 mm^(2)/(kg·s^(2)).However,with the increase of the number of free surfaces in subsequent excavation blasting,the λ_(g) of the double free surfaces and the three free surfaces decrease to 1.36 and 0.28 mm^(2)/(kg·s^(2)),and the reduction rates of the peak particle velocity(PPV)of the frequency band are 65%and 37%.Besides,the energy of the subsequent explosion will be used more for breaking and throwing the rock mass,and the main frequency of it will also develop from low frequency to high frequency band(31.25−62.50 Hz).Therefore,the influence of the number of free surfaces on the vibration energy distribution and attenuation law should be considered in the design of underwater controlled blasting.Using this regularity and characteristic,it is possible to more accurately determine the controlled explosive charge of each segment and reduce the resonance hazard to surrounding structures.
作者
马晨阳
吴立
孙苗
MA Chenyang;WU Li;SUN Miao(Engineering Research Center of Rock-Soil Drill&Excavation and Protection of the Ministry of Education,China University of Geosciences,Wuhan 430074,Hubei,China;Faculty of Engineering,China University of Geosciences,Wuhan 430074,Hubei,China)
出处
《爆炸与冲击》
EI
CAS
CSCD
北大核心
2022年第1期142-153,共12页
Explosion and Shock Waves
基金
国家自然科学基金(41672260)。
关键词
水下钻孔爆破
自由面
时频分析
振动衰减
underwater drilling blasting
free surface
time-frequency analysis
vibration attenuation
