浅层地震勘查技术用于工程地基稳定性评价问题探讨
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摘要
对埋深≤180m的局部开采煤层设计数学模型:圆形孔洞半径30m,孔中心深度180m,并利用高斯射线束法计算其合成记录。从自激自收的记录剖面及水平叠加时间剖面可见,除煤层反射波外,圆形孔洞的顶部在时间剖面上存在典型的绕射波,而其底部也能存在较弱的绕射波;当圆形孔洞塌陷后,由于其上覆地层的塌陷和离析,干扰波不但会增加,而且剖面的地震相也会更加复杂。根据在多个地区开展浅层地震勘查工作经验,对一般沉陷区或严重沉陷区的特征进行了总结,并提出了其判断原则。以邯郸鹏泰钢铁有限公司技改工程地基稳定性评价为例,利用该方法,共查明该区1处Ⅲ类异常区(严重沉降区)和4块II类异常区块或条带(一般沉降区),经4个注浆孔验证,均打到了采空区或巷道,位置及深度与勘查报告完全一致。
Mathematical model is designed for locally mining coal seams with buried depth ≤ 180m: radius of round cave 30m,depth of cave center 180m,using Gaussian ray beam method calculates its synthetic record.From self-shooting and self receiving record sections and horizontal stacking time sections can see except coal seam reflection waves,typical diffracted waves existed on time section on top of round cave,while bottom also have weaker diffracted waves existed.When round cave is collapsed,lead to overlying strata collapse and fall to pieces,distributing waves increasing,seismic facies on sections also more complicated.Based on experiences from shallow seismic prospecting practices in many regions,summed up characteristics of common and serious subsidence areas,and have advanced their judging principles.To take the foundation stability appraisal of Handan Pengtai Steel Co.Ltd.technical innovation engineering as an example,by the use of this method,found out 1 category III anomalous region(serious subsidence area) and 4 category II anomalous regions or strips(common subsidence area),4 grouting boreholes have made sure the existing of gob area or workings,and their location and depth are all accord with exploration report.
Mathematical model is designed for locally mining coal seams with buried depth ≤ 180m: radius of round cave 30m,depth of cave center 180m,using Gaussian ray beam method calculates its synthetic record.From self-shooting and self receiving record sections and horizontal stacking time sections can see except coal seam reflection waves,typical diffracted waves existed on time section on top of round cave,while bottom also have weaker diffracted waves existed.When round cave is collapsed,lead to overlying strata collapse and fall to pieces,distributing waves increasing,seismic facies on sections also more complicated.Based on experiences from shallow seismic prospecting practices in many regions,summed up characteristics of common and serious subsidence areas,and have advanced their judging principles.To take the foundation stability appraisal of Handan Pengtai Steel Co.Ltd.technical innovation engineering as an example,by the use of this method,found out 1 category III anomalous region(serious subsidence area) and 4 category II anomalous regions or strips(common subsidence area),4 grouting boreholes have made sure the existing of gob area or workings,and their location and depth are all accord with exploration report.
引文
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[3]肖建华.关于孔隙岩石的一般波动理论[J].石油地球物理勘探,1998,33(5).
[4]肖建华.岩石中的各项异性波理论研究[J].石油地球物理勘探,1998,33(增刊2).
[2]Gladwell G M L,范天佑译,经典弹性理论中的接触问题[M],北京:北京理工大学出版社,1991.
[3]肖建华.关于孔隙岩石的一般波动理论[J].石油地球物理勘探,1998,33(5).
[4]肖建华.岩石中的各项异性波理论研究[J].石油地球物理勘探,1998,33(增刊2).
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