城市地下断裂构造可控震源地震勘探试验研究

Experimental study on vibroseis seismic exploration in urban underground fault structure

在城市地下空间开发过程中,断裂构造是引起地质灾害的重要因素之一,有效探查断层的位置、规模及深度,具有重要的意义。地震反射波法已逐渐应用到城市地下空间异常地质构造地探查,但城市地表表层地震地质条件复杂,环境噪音大,硬质路面检波器耦合较差,传统锤击震源能量弱、衰减快、信噪比低,勘探精度很难达到规范要求。这里以某城市勘探区探查地下断裂构造为例,利用可控震源激发,从能量、信噪比、频率等方面对试验资料进行分析,确定适合该区可控震源施工参数,提高了地震时间剖面的分辨率和探查精度,取得了良好的探查应用效果。

In the process of urban underground space development,the fault structure is one of the important factors that cause the geological disasters.It is of great significance to effectively detect the location,size and depth of the fault.Seismic reflection wave method has been gradually applied to the exploration of abnormal geological structure of urban underground space.But the urban surface seismic geological conditions are complex,high noise and poor detector coupling in hard pavement.Traditional hammer energy sources are weak,fast decay,low signal to noise ratio,and it is difficult to meet the requirements of the specification.Taking the exploration of underground structure in a city as an example,the vibrator was used to carry out excitation,analysis was conducted for test data from energy,SNR and frequency to determine the operation parameters.It can enhance the resolution and exploration precision of seismic time section,obtaining more satisfied exploration results.