盾构下穿球场段超高密度地震背景噪声探测

Ultra⁃high⁃density Seismic Ambient Noise Detection of Shield Underpassing Court

为解决在受限场地内无法完整开展地质钻探和有损探测的问题,结合广州地铁12号线广恒盾构区间下穿高尔夫练习场项目,综合考虑地形、环境影响,对现有物探方法进行比选,以确定勘探方案。研究本测区的地球物理条件,明确超高密度地震背景噪声法,实现不同风化程度岩层的层位划分,通过前期试验,论证该探测技术在本测区的适用性。分析探测数据质量的可靠性,同时对比已有钻探资料、掘进揭露地层的一致性,针对性提出建议。研究结果表明,预先设置试验段可确定合理的道间距,短断面宜采用2m道间距,长断面宜采用4m道间距。物探与钻探揭露层位层序基本吻合,各层位置与验证孔误差在2m内,误差可控制在5%内。该方法对单一地层适用性较好,因此需根据地层波速情况,分析硬岩与软土的交叠位置,并进行加密检测。

To solve the problem that geological drilling and destructive detection can not be completely carried out in restricted site,this study based on Guang-Heng section of Guangzhou Metro Line 12 shield under-passing the golf court project.Firstly,comprehensively considering the requirements of topographical conditions and environmental impact,the existing geophysical prospecting methods were compared to determine the exploration scheme.Additionally,the geophysical conditions for test region were studied,and the ultra-high density seismic ambient noise detection can realize the stratification division of the rock strata with different weathering degrees,herein,the practical applicability for this method was demonstrated through the preliminary test.Finally,the reliability of the probe data quality was analyzed,and the consistency with the existing drilling data and excavation exposed strata was compared.The results show that,the reasonable receiver interval can be determined by pre-setting the test section,and it is suggested to adopt a 2m receiver interval for the short section and a 4m receiver interval for the long section.The geophysical exploration is basically consistent with drilling,and error between the position of each layer is within 2m,and the error can be controlled within 5%.This method is suitable for the single stratum,so it is necessary to analyze the overlapping position of hard rock,and soft soil according to stratum wave velocity and encrypted detection should be carried out.