Active-source surface wave exploration is advantageous because it has high imaging accuracy,is not affected by high-speed layers,and has a low cost;thus,it has unique advantages for investigating shallow surface struc...Active-source surface wave exploration is advantageous because it has high imaging accuracy,is not affected by high-speed layers,and has a low cost;thus,it has unique advantages for investigating shallow surface structures.For the development and utilization of urban underground space,two parameters in the shallow surface are important,namely,the shear wave velocity(V_(S))and the predominant period of the site,which determine the elevation and aseismic grade of the building design.The traditional method is mainly to obtain the two above-mentioned parameters through testing and measuring drilling samples.However,this method is extremely expensive and time consuming.Therefore,in this research,we used the multichannel surface wave acquisition method to extract the fundamental dispersion curve of single-shot data by using the phase shift method and obtain the V_(S) characteristics in the uppermost 40 m by inversion.We arrived at the following two conclusions based on the V_(S) profile.First,the study area can be roughly divided into five layers,among which the layers 0−8 m,14−20 m,and 20−30 m are low-velocity layers,corresponding to miscellaneous fill,a water-bearing sand layer,and a sand layer;therefore,the V_(S) is relatively low.In contrast,the layers at 8−14 m and 30−40 m are high-velocity layers that are mainly composed of clay,with a relatively better compactness and relatively high V_(S) values.In addition,a low-speed anomaly appears abruptly in the high-speed area at 20−40 m.This anomaly,when combined with geological data,suggests that it is an ancient river channel.Second,from the V_(S) value,the V_(Se)(equivalent shear wave velocity)was calculated.The construction site soil was categorized as class III,with good conditions for engineering geology.In addition,we calculated the predominant period of the site to be 0.56-0.77 s based on the V_(S).Therefore,in the overall structural design of the foundation engineering,the natural vibration period of the structure should be strictly controlled to avoid the predominant period of the site.展开更多
In Rayleigh wave exploration,the inversion of dispersion curves is a crucial step for obtaining subsurface stratigraphic information,characterized by its multi-parameter and multi-extremum nature.Local optimization al...In Rayleigh wave exploration,the inversion of dispersion curves is a crucial step for obtaining subsurface stratigraphic information,characterized by its multi-parameter and multi-extremum nature.Local optimization algorithms used in dispersion curve inversion are highly dependent on the initial model and are prone to being trapped in local optima,while classical global optimization algorithms often suffer from slow convergence and low solution accuracy.To address these issues,this study introduces the Osprey Optimization Algorithm(OOA),known for its strong global search and local exploitation capabilities,into the inversion of dispersion curves to enhance inversion performance.In noiseless theoretical models,the OOA demonstrates excellent inversion accuracy and stability,accurately recovering model parameters.Even in noisy models,OOA maintains robust performance,achieving high inversion precision under high-noise conditions.In multimode dispersion curve tests,OOA effectively handles higher modes due to its efficient global and local search capabilities,and the inversion results show high consistency with theoretical values.Field data from the Wyoming region in the United States and a landfill site in Italy further verify the practical applicability of the OOA.Comprehensive test results indicate that the OOA outperforms the Particle Swarm Optimization(PSO)algorithm,providing a highly accurate and reliable inversion strategy for dispersion curve inversion.展开更多
面波勘探作为浅层地球物理勘探的重要方法,凭借其无损探测、高效采集和经济优势,在工程地质勘察、城市地下空间开发及地质灾害评估等领域得到广泛应用。然而,传统震源装置在复杂地质条件下普遍存在激发效率低、环境适应性差等问题,导致...面波勘探作为浅层地球物理勘探的重要方法,凭借其无损探测、高效采集和经济优势,在工程地质勘察、城市地下空间开发及地质灾害评估等领域得到广泛应用。然而,传统震源装置在复杂地质条件下普遍存在激发效率低、环境适应性差等问题,导致探测精度受限,制约了该方法在特殊场景下的工程适用性。本研究基于冲击地震波场耦合理论,采用TDIS(Tong Du Impact Source,TDIS)可控冲击震源技术,针对人工锤击、落锤震源和可控冲击震源三类激发装置,系统对比其在不同地质环境中的适应性。通过在强环境噪声干扰的城区、厚覆盖层郊野及薄松散层丘陵三类典型场地开展对比试验,综合原始数据质量、频散谱能量聚焦特性、反演模型与地质验证结果的一致性,得出以下结论:1)在城区强噪声背景下,可控冲击震源较人工锤击具有显著抗干扰优势,频散曲线连续性明显改善;2)相较于落锤震源,可控冲击震源在复杂地形适应性、设备便携性及连续采集效率方面更具优势;3)厚覆盖层场地中,可控震源展现出更大的有效探测深度;4)对于基岩埋深较浅的丘陵区,三类震源的勘探效果趋于一致。研究成果验证了可控冲击震源在提升复杂环境下面波勘探精度与探测深度方面的技术优势。展开更多
基金This study was supported by the National Natural Science Foundation of China(grant nos.42074115,41574094)the National Key R&D Program of China(grant no.2017YFC0601301)+1 种基金the Geological Survey Project of the China Geological Survey(grant no.DD20189132)the Key Laboratory of Deep-Earth Dynamics,Ministry of Natural Resources(grant no.J1901-3).
文摘Active-source surface wave exploration is advantageous because it has high imaging accuracy,is not affected by high-speed layers,and has a low cost;thus,it has unique advantages for investigating shallow surface structures.For the development and utilization of urban underground space,two parameters in the shallow surface are important,namely,the shear wave velocity(V_(S))and the predominant period of the site,which determine the elevation and aseismic grade of the building design.The traditional method is mainly to obtain the two above-mentioned parameters through testing and measuring drilling samples.However,this method is extremely expensive and time consuming.Therefore,in this research,we used the multichannel surface wave acquisition method to extract the fundamental dispersion curve of single-shot data by using the phase shift method and obtain the V_(S) characteristics in the uppermost 40 m by inversion.We arrived at the following two conclusions based on the V_(S) profile.First,the study area can be roughly divided into five layers,among which the layers 0−8 m,14−20 m,and 20−30 m are low-velocity layers,corresponding to miscellaneous fill,a water-bearing sand layer,and a sand layer;therefore,the V_(S) is relatively low.In contrast,the layers at 8−14 m and 30−40 m are high-velocity layers that are mainly composed of clay,with a relatively better compactness and relatively high V_(S) values.In addition,a low-speed anomaly appears abruptly in the high-speed area at 20−40 m.This anomaly,when combined with geological data,suggests that it is an ancient river channel.Second,from the V_(S) value,the V_(Se)(equivalent shear wave velocity)was calculated.The construction site soil was categorized as class III,with good conditions for engineering geology.In addition,we calculated the predominant period of the site to be 0.56-0.77 s based on the V_(S).Therefore,in the overall structural design of the foundation engineering,the natural vibration period of the structure should be strictly controlled to avoid the predominant period of the site.
基金sponsored by China Geological Survey Project(DD20243193 and DD20230206508).
文摘In Rayleigh wave exploration,the inversion of dispersion curves is a crucial step for obtaining subsurface stratigraphic information,characterized by its multi-parameter and multi-extremum nature.Local optimization algorithms used in dispersion curve inversion are highly dependent on the initial model and are prone to being trapped in local optima,while classical global optimization algorithms often suffer from slow convergence and low solution accuracy.To address these issues,this study introduces the Osprey Optimization Algorithm(OOA),known for its strong global search and local exploitation capabilities,into the inversion of dispersion curves to enhance inversion performance.In noiseless theoretical models,the OOA demonstrates excellent inversion accuracy and stability,accurately recovering model parameters.Even in noisy models,OOA maintains robust performance,achieving high inversion precision under high-noise conditions.In multimode dispersion curve tests,OOA effectively handles higher modes due to its efficient global and local search capabilities,and the inversion results show high consistency with theoretical values.Field data from the Wyoming region in the United States and a landfill site in Italy further verify the practical applicability of the OOA.Comprehensive test results indicate that the OOA outperforms the Particle Swarm Optimization(PSO)algorithm,providing a highly accurate and reliable inversion strategy for dispersion curve inversion.
文摘面波勘探作为浅层地球物理勘探的重要方法,凭借其无损探测、高效采集和经济优势,在工程地质勘察、城市地下空间开发及地质灾害评估等领域得到广泛应用。然而,传统震源装置在复杂地质条件下普遍存在激发效率低、环境适应性差等问题,导致探测精度受限,制约了该方法在特殊场景下的工程适用性。本研究基于冲击地震波场耦合理论,采用TDIS(Tong Du Impact Source,TDIS)可控冲击震源技术,针对人工锤击、落锤震源和可控冲击震源三类激发装置,系统对比其在不同地质环境中的适应性。通过在强环境噪声干扰的城区、厚覆盖层郊野及薄松散层丘陵三类典型场地开展对比试验,综合原始数据质量、频散谱能量聚焦特性、反演模型与地质验证结果的一致性,得出以下结论:1)在城区强噪声背景下,可控冲击震源较人工锤击具有显著抗干扰优势,频散曲线连续性明显改善;2)相较于落锤震源,可控冲击震源在复杂地形适应性、设备便携性及连续采集效率方面更具优势;3)厚覆盖层场地中,可控震源展现出更大的有效探测深度;4)对于基岩埋深较浅的丘陵区,三类震源的勘探效果趋于一致。研究成果验证了可控冲击震源在提升复杂环境下面波勘探精度与探测深度方面的技术优势。
