【作者】 赵阳；

【导师】 杨为民； 许新骥； 刘征宇；

【作者基本信息】 山东大学 ， 交通运输（专业学位）， 2023， 硕士

【摘要】 在城市地下隧道等地下工程建设和开发中,盾构机施工方法因其具有自动化程度高、施工速度快、经济效益高等显著优势而被广泛应用。然而,城市地下浅层地质条件复杂多变、地表勘察环境复杂环境,钻探等方法难以覆盖隧道工程全线,前期难以全部探清地下地质情况。对此,亟需在隧道施工期开展超前地质预报,探明地质情况并进行预先防控,是保证盾构机安全掘进的重要前提。相较于传统钻爆法施工隧道,盾构机施工环境更为复杂,传统物探方法因受限于盾构隧道洞内空间和环境,难以实现远距离和高分辨率的探测。综上,开展适用于城市盾构隧道不良地质精细探测方法研究是城市地下隧道安全建设的迫切需要。针对城市盾构隧道不良地质探测难题,本文以盾构掘进噪声源利用为核心,提出了基于盾构掘进源“地-孔-洞”多波场联合的不良地质超前探测方法创新思路:以盾构机施工震动作为震源,孔中、地表观测掘进噪声源诱发的多波场信息并联合利用,有效扩展了地球物理场的观测孔径并增加了响应波场信息,支撑提升了前方地质情况探测的准确性。围绕上述思路,将城市盾构隧道特点与浅地表多波场波速反演结合,重点开展了“‘地-孔-洞’联合超前探测多波场特征与观测方式、基于聚类约束和多虚源叠加的孔中层析成像反演方法、基于层析成像信息先验的面波波速反演方法”三项研究内容,并针对城市地下盾构施工隧道典型不良地质,开展了数值模拟试验,验证了本文提出探测方法的可行性,最后在广州供电局电力隧道等工程验证了方法的实用性。(1)基于“地-孔-洞”联合超前探测多波场特征与观测方式。针对盾构隧道传统洞内地震勘探方法观测系统受限问题,以洞内盾构机掘进噪声为震源,提出了孔中和地表联合接收的观测方式。其中,重点针对孔中和地表观测掘进源波场特征认识不清的问题,分析了在地表和孔中观测掘进震动噪声的特点及不良地质的虚源波场响应规律,结合多类型波场对盾构前方探测目标区的响应敏感性,实现了优势波场类型的选取;进而,基于傅里叶变换、频率贝塞尔变换和连续小波变换等方法,实现有效波场信息的分离提取;在此基础上,确定了盾构施工隧道“地-孔-洞”联合观测系统的优选布设参数,实现了不良地质波场响应的有效感知,为后续掘进源面波、体波波速反演奠定了数据基础。(2)基于聚类约束和多虚源叠加的孔中层析成像反演方法。针对盾构隧道前方纵波波速求取难题,开展了层析成像波速反演方法研究。围绕孔-隧透射观测模式下射线密度不足,导致传统初至走时层析成像方法计算结果准确性低的问题,提出了基于聚类分析约束的层析成像反演方法,重点改进了稀疏射线密度条件下层析成像的反演效果;进而,结合盾构隧道连续施工的特点,以多掘进面虚源记录和地表虚源记录为补充,提出了“地-孔-洞”多虚源重构和射线叠加的反演策略,对探测目标区的射线密度进行了补充;上述方法相结合,提升了盾构施工隧道前方地质结构波速的计算准确性。(3)基于层析成像信息先验的面波波速反演方法。针对面波反演过程中依赖初始模型及一维波速反演的难题。对此,鉴于孔-隧层析成像方法可获得波速的水平变化特征,从中提取出了波速变化特征与地层分层特征,将其作为面波反演初始模型,有效压制了因初始模型不准而导致的反演多解性强和准确性低等问题;进而,提出了基于层析成像反演波速先验的面波波速反演方法,实现了面波、体波多波场信息联合利用,提高了面波波速反演的准确性;在此基础上,形成了“地-孔-洞”多波场联合的不良地质超前探测实现方法,为城市地下盾构施工不良地质超前探测提供了可靠方法。在上述研究基础上,依托广州供电局增城南电力隧道工程开展了现场试验,获取了盾构隧道前方岩土体波速分布,验证了本文方法的可行性。更多还原

【Abstract】 In the construction and development of urban underground tunnels and other underground projects,shield tunneling machine construction methods are widely used due to their significant advantages such as high automation,fast construction speed,and high economic benefits.However,due to the complex and variable geological conditions of the shallow underground layer in cities and the complex environment of surface exploration,drilling and other methods are difficult to cover the entire tunnel project line,and it is difficult to fully explore the underground geological situation in the early stage.In this regard,it is urgent to carry out advanced geological prediction during tunnel construction,explore geological conditions,and carry out pre prevention and control,which is an important prerequisite to ensure the safe excavation of shield tunneling machines.Compared to traditional drilling and blasting methods for tunnel construction,the construction environment of shield tunneling machines is more complex.Traditional geophysical methods are limited by the space and environment inside the shield tunnel,making it difficult to achieve long-distance and high-resolution detection.In summary,conducting research on fine geological detection methods suitable for urban shield tunneling is an urgent need for the safety construction of urban underground tunnels.In response to the difficult problem of poor geological detection in urban shield tunneling,this article focuses on the utilization of shield tunneling noise sources and proposes an innovative approach for advanced detection of poor geological conditions based on the combination of shield tunneling source "ground hole tunnel" multi wave fields:using shield tunneling machine construction vibration as the source,observing the multi wave field information induced by excavation noise sources in the hole and on the surface,and jointly utilizing it,Effectively expanding the observation aperture of geophysical fields and increasing response wave field information,supporting and improving the accuracy of geological exploration ahead.Based on the above ideas,the characteristics of urban shield tunnels are combined with shallow surface multi wave field wave velocity inversion,with a focus on three research contents:"joint advance detection of multi wave field characteristics and observation methods of ’ground hole tunnel’,borehole tomography inversion method based on clustering constraints and multi virtual source stacking,and surface wave velocity inversion method based on tomography information prior".The research focuses on typical adverse geology of urban underground shield tunnel construction,Numerical simulation experiments were conducted to verify the feasibility of the detection method proposed in this paper.Finally,the practicality of the method was verified in projects such as the power tunnel of Guangzhou Power Supply Bureau.(1)Based on the joint advanced detection of multi wave field characteristics and observation methods of surface-drill-tunnel.In response to the limited observation system of traditional seismic exploration methods in shield tunnels,a joint observation method of borehole and surface reception is proposed using the excavation noise of shield tunneling machines as the source.Among them,the focus is on the problem of unclear understanding of the characteristics of excavation source wave fields observed in the borehole and surface.The characteristics of excavation vibration noise observed on the surface and in the borehole,as well as the virtual source wave field response law of unfavorable geology,were analyzed.Combined with the sensitivity of multiple types of wave fields to the detection target area in front of the shield tunnel,the selection of dominant wave field types was achieved;Furthermore,based on methods such as Fourier transform,frequency Bessel transform,and continuous wavelet transform,effective wave field information can be separated and extracted;On this basis,the optimal layout parameters of the "ground hole tunnel" joint observation system for shield tunneling were determined,achieving effective perception of adverse geological wave field response,and laying a data foundation for subsequent inversion of source surface wave and body wave velocities in excavation.(2)A borehole tomography inversion method based on clustering constraints and multi virtual source stacking.In response to the difficulty of obtaining the longitudinal wave velocity in front of the shield tunnel,a tomography imaging wave velocity inversion method was studied.A tomography inversion method based on clustering analysis constraints is proposed to address the issue of insufficient ray density in the hole tunnel transmission observation mode,which leads to low accuracy in the calculation results of traditional first break travel time tomography methods.The focus is on improving the inversion effect of tomography under sparse ray density conditions;Furthermore,based on the characteristics of continuous construction of shield tunnels,a surface-drill-tunnel multi virtual source reconstruction and ray stacking inversion strategy is proposed,supplemented by multiple excavation face virtual source records and surface virtual source records,to supplement the ray density in the detection target area;The combination of the above methods has improved the accuracy of calculating the wave velocity of geological structures in front of shield tunneling.(3)A surface wave velocity inversion method based on prior information from tomographic imaging.The problem of relying on the initial model and onedimensional wave velocity inversion in the process of surface wave inversion is addressed.In this regard,considering that the hole tunnel tomography method can obtain the horizontal variation characteristics of wave velocity,the wave velocity variation characteristics and stratigraphic stratification characteristics have been extracted from them,and they have been used as the initial model for surface wave inversion,effectively suppressing the problems of strong inversion multiplicity and low accuracy caused by inaccurate initial models;Furthermore,a surface wave velocity inversion method based on tomography inversion wave velocity prior was proposed,which achieved the joint utilization of surface wave and bulk wave field information and improved the accuracy of surface wave velocity inversion;On this basis,a surfacedrill-tunnel multi wave field joint implementation method for advanced detection of unfavorable geology has been formed,providing a reliable method for advanced detection of unfavorable geology in urban underground shield tunneling construction.On the basis of the above research,on-site tests were conducted on the Zengcheng South Power Tunnel project of Guangzhou Power Supply Bureau to obtain the wave velocity distribution of the rock and soil in front of the shield tunnel,verifying the feasibility of the method proposed in this paper.更多还原