Urban shallow subsurface geological exploration method

Abstract

The present application provides a kind of urban shallow surface geological detection method, adopts transient electromagnetic method and seismic wave method to detect, according to the detection result, determine hole information, subsequently carry out the result near imaging based on the fusion of cross-hole electromagnetic wave CT and cross-hole elastic wave CT, further carry out accurate physical exploration to adverse geological body;Surface and hole geophysical prospecting exploration results will provide target positioning information for geological drilling, carry out real shape imaging of the fusion of borehole logging and hole laser scanning, improve the efficiency and accuracy of geological drilling.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geological exploration, and particularly relates to a method for exploring the geological conditions of the shallow surface of a city. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] The construction of underground projects such as subways and tunnels will inevitably encounter common adverse geology such as faults, broken rock mass, water-rich conditions, karst caves and soft rock mass. Therefore, it is very important to carry out advanced exploration of adverse geological bodies during the construction stage to ensure construction safety and progress.

[0004] The advanced exploration technology of adverse geological structures has made great and comprehensive progress over the past few decades, including destructive exploration methods such as advanced pilot tunneling and advanced drilling methods, and non-destructive exploration methods such as seismic emission, electromagnetic and direct current methods. It is worth noting that the transition from a single exploration method to a comprehensive exploration of multiple methods is crucial for reducing the ambiguity of exploration results and improving the accuracy of exploration, and is one of the important development trends of current geological exploration methods. In addition, when exploring the geological conditions of the shallow surface of a city, not only is the exploration space limited, but also many interferences such as city noise cannot be ignored, which further increases the difficulty and challenge of geological exploration.

[0005] Therefore, how to comprehensively and accurately explore the geological conditions of the shallow surface of a city is a problem that needs to be solved at present. SUMMARY

[0006] In order to overcome the shortcomings of the prior art, the present application provides a method for exploring the geological conditions of the shallow surface of a city, which realizes more comprehensive and accurate geological exploration of the shallow surface of a city by using "ground geophysical exploration + borehole geophysical exploration + geological drilling" and combining the "priori + posteriori dual driving" exploration method.

[0007] To achieve the above purpose, the first aspect of the present application provides a method for exploring the geological conditions of the shallow surface of a city, comprising:

[0008] The shallow surface geological anomaly area is obtained by using the electromagnetic method and the seismic emission method to jointly explore the ground physical exploration mode of the area to be surveyed.

[0009] The shallow surface geological anomaly area is obtained by using the electromagnetic method and the seismic emission method to jointly explore the ground physical exploration mode of the area to be surveyed.

[0010] The shape features of the underground structure obtained by the in-hole physical detection are taken as prior information, and the geological drilling is carried out by using the borehole logging technology and the laser scanning mode to identify the abnormal body existing underground and evaluate the size, shape and position of the abnormal body;

[0011] The identification result obtained by the geological drilling is taken as posterior information of the in-hole physical detection to reversely guide the process of the in-hole physical detection;

[0012] The result obtained by the in-hole physical detection is taken as posterior information of the ground physical detection to reversely guide the process of the ground physical detection;

[0013] The above steps are repeated until the detection of all the areas to be detected is completed.

[0014] The above one or more technical solutions have the following beneficial effects:

[0015] In the present application, the combined electric-seismic collaborative detection mode is adopted for detection, the detection result is taken as prior information of the in-hole physical detection, then the in-hole physical detection based on the fusion of the cross-hole electromagnetic wave CT and the cross-hole elastic wave CT is carried out to further accurately physically explore the adverse geological body; the result of the in-hole physical detection is taken as prior information of the geological drilling, the geological drilling is carried out by using the borehole logging technology and the laser scanning mode to more accurately identify the abnormal body existing underground, the identification result obtained by the geological drilling is taken as posterior information of the in-hole physical detection to reversely guide the process of the in-hole physical detection and improve the detection accuracy; the result obtained by the in-hole physical detection is taken as posterior information of the ground physical detection to reversely guide the process of the ground physical detection and improve the exploration accuracy; through the "ground physical detection + in-hole physical detection + geological drilling", and in combination with the "prior + posterior double driving" detection method, the more comprehensive and accurate geological exploration of the urban shallow surface is realized.

[0016] The advantages of the additional aspects of the present application will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their description are used to explain the present application, and do not constitute improper limitations on the present application.

[0018] Figure 1 The flow chart of the city shallow surface geological exploration method in the embodiment one of the present application. DETAILED DESCRIPTION

[0019] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0020] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application.

[0021] In the case of no conflict, the embodiments in the application and the features in the embodiments can be combined with each other.

[0022] Embodiment one

[0023] The embodiment discloses a city shallow surface geological exploration method, comprising:

[0024] The electromagnetic method and the seismic emission method are combined to perform ground physical exploration on the area to be surveyed, and a shallow surface geological anomaly area is obtained.

[0025] The shallow surface geological anomaly area is used as prior information, and cross-hole electromagnetic wave CT and cross-hole elastic wave CT fusion are used for physical exploration in the hole to further reveal the morphological characteristics of the underground structure.

[0026] The morphological characteristics of the underground structure obtained by the physical exploration in the hole are used as prior information, and drilling technology and laser scanning are used for geological drilling to more thoroughly identify abnormal bodies such as faults, karst caves, and fracture zones, and the size, shape, and position of the abnormal bodies are evaluated by observing and describing the rock cores taken from the drilling and recording the drilling.

[0027] The results of the geological drilling are used as posterior information of the physical exploration in the hole to reversely guide the field implementation, data processing, and result interpretation of the physical exploration in the hole, thereby improving the detection accuracy.

[0028] The results of the physical exploration in the hole are used as posterior information of the ground physical exploration to reversely guide the field implementation, data processing, and result interpretation of the ground physical exploration, thereby improving the accuracy of the exploration.

[0029] The above steps are repeated until the exploration of all areas to be explored is completed.

[0030] Combination Figure 1 The city shallow surface geological exploration method proposed in the embodiment is described in detail.

[0031] Step 1: Exploration preparation, the surface topographic characteristics and hydrogeological conditions of the area to be explored need to be understood in detail.

[0032] Step 2: Some field experiments are carried out in advance for the area to be explored, and relevant parameters suitable for the area to be explored in the selected method are obtained, such as spectral characteristics and frequency range, etc., which are used to more accurately identify and predict underground adverse geology;

[0033] Step 3: According to the spatial distribution characteristics of the exploration area, appropriate measuring points are selected, and a ground geophysical observation system is determined, including a seismic wave reflection observation system, a micro-motion exploration observation system, a high-density resistivity observation system, and a transient electromagnetic observation system. The measuring points should be evenly distributed as much as possible to ensure that comprehensive and accurate data can be obtained, and the measuring points should be appropriately increased on both sides or around the building (structure) so that the influence of the building (structure) can be eliminated through data processing and analysis;

[0034] Among them, the micro-motion exploration can realize the non-destructive and convenient detection of disaster sources in the urban traffic scene by collecting urban traffic noise data, determining the spectral characteristics and dominant frequency range of noise signals in complex traffic scenes, and realizing the "noise as source" of disaster sources in the urban traffic scene.

[0035] Step 4: The above four methods are used to carry out geological exploration, and the collected data are preprocessed, denoised, corrected and other necessary data processing steps, and the data are imaged;

[0036] Step 5: The imaging results of ground exploration are interpreted to obtain the geological information of the exploration area and determine the shallow surface geological anomaly area. The above steps are used to realize the ground electric-seismic collaborative exploration;

[0037] Step 6: According to the spatial distribution position and scale of the geological anomaly area obtained by the electric-seismic collaborative exploration, a borehole geophysical exploration scheme is designed, and the selection of measuring point spacing should consider the detection accuracy and efficiency. Smaller measuring point spacing should be used at the boundary of the anomaly area; in the relatively uniform area inside the anomaly body, the measuring point spacing can be appropriately increased to improve the work efficiency on the premise of ensuring the detection effect;

[0038] Step 7: After drilling according to the measuring points, the cross-hole electromagnetic wave CT and cross-hole elastic wave CT fusion method is used for borehole physical exploration. The parameters of the two methods are coordinated in the selection of data acquisition parameters, mainly involving the selection of wave frequency, so as to make the propagation characteristics of the two waves have good complementarity in the detection area, so as to better reflect the different characteristics of the geological body;

[0039] Step 8: The information of electromagnetic wave and elastic wave is combined organically by using weighted average method and according to the importance and reliability of different geological characteristics to give corresponding weight, and the near distance imaging of cross-hole electromagnetic wave CT and cross-hole elastic wave CT fusion is interpreted, the range of relatively low velocity area in wave velocity map is used to judge the shape characteristics of poor geological structure in the survey area, and the scale and location of poor geological body are compared with the results of ground geophysical prospecting as posterior information to correct the selection of data processing parameters and the judgment of interpretation criteria in ground geophysical prospecting;

[0040] Step 9: First, the drilling measurement points are set according to the spatial position of the geological anomaly body determined by surface geophysical prospecting and borehole geophysical prospecting, and the measurement point range should fully cover the geological anomaly body, and the relatively developed geological anomaly body should be drilled, secondly, the minimum depth of the drilling hole is determined according to the depth range of the geological anomaly body determined by surface geophysical prospecting and borehole geophysical prospecting, and the drilling hole should at least penetrate the bottom of the anomaly body, if the depth of the anomaly body is large or the geological condition under the anomaly body is unknown, the drilling hole should be deepened appropriately;

[0041] Step 10: During the process of geological drilling, rock and soil samples are taken along the hole depth, which are used to measure the physical and mechanical properties of rock and soil, and then the distance between the sensor and the target is determined by laser scanning in the hole, emitting laser pulses and measuring the round trip time of the pulses, the position and size information of the poor geological body can be obtained, and the shape characteristics can be obtained by multiple scanning and measurement;

[0042] Step 11: After the detection is completed, the results of geological drilling are summarized to determine whether the observation system needs to be adjusted, whether the data processing parameters or imaging method needs to be adjusted, and the matters needing attention in the interpretation process.

[0043] Step 12: If necessary, further compare the results of borehole geophysical prospecting and ground geophysical prospecting, analyze whether there is a part to be improved in ground geophysical prospecting, so as to guide the next stage of ground geophysical prospecting, data processing, imaging and interpretation.

[0044] Step 13: Through the adjustment and correction of ground and borehole geophysical prospecting, steps 1-9 are repeated to carry out the next stage of double drive geological exploration.

[0045] In this embodiment, first, the prior process is realized in the detection stage, that is, the electromagnetic method and seismic wave method are cooperatively detected on the ground, and the detection results are used to guide the borehole geophysical prospecting, provide the constraint information of hole position and depth, etc., to improve the accuracy and inversion accuracy of the near imaging of cross-hole electromagnetic wave CT and cross-hole elastic wave CT fusion in the hole, the results of surface and borehole geophysical prospecting will further constrain the geological drilling, so that the target is stronger, and the target positioning information is provided for the drilling, and the accuracy of the real shape imaging of drilling logging and borehole laser scanning fusion is improved.

[0046] Secondly, after the completion of the detection, the posterior process is realized by analysis and summary, that is, the results of geological drilling will guide the implementation of borehole geophysical prospecting in the reverse, further correct the implementation, data processing and result interpretation process, and also guide the detection of ground geophysical prospecting to a certain extent, to continuously improve the accuracy of ground geophysical prospecting, and the results of borehole geophysical prospecting will also play an important guiding and correcting role in the ground detection process.

[0047] Through the improved joint detection of ground-borehole-drill, guided and corrected by priori and posteriori double driving process, the whole geological detection process forms a closed loop operation, each part complements each other, and promotes the whole detection method to high precision and high inversion accuracy.

[0048] In this embodiment, the ground geophysical prospecting module adopts the joint electric-seismic cooperative detection of seismic wave reflection method, micro-motion exploration, high-density resistivity method and transient electromagnetic method. The detection results will provide priori information for subsequent borehole geophysical prospecting, so as to improve the inversion accuracy of borehole geophysical prospecting method. Then, the result near imaging based on the fusion of cross-hole electromagnetic wave CT and cross-hole elastic wave CT is carried out, and the precise physical exploration of the adverse geological body is further carried out. The exploration results of ground and borehole geophysical prospecting will provide target positioning information for geological drilling, and the real shape imaging of the fusion of drilling and borehole laser scanning is carried out, so as to improve the efficiency and precision of geological drilling, and realize a series of priori processes. Through the results of geological drilling and borehole laser scanning imaging, the imaging accuracy of ground and borehole geophysical prospecting is reversedly corrected, the implementation and imaging of ground and borehole geophysical prospecting are guided, and the inversion accuracy of geophysical prospecting is improved.

[0049] Those skilled in the art should understand that each module or step of the present application described above can be realized by a general computer device. Alternatively, they can be realized by program codes executable by a computing device, so that they can be stored in a storage device and executed by a computing device, or they can be respectively manufactured into each integrated circuit module, or a plurality of modules or steps among them can be manufactured into a single integrated circuit module to realize. The present application is not limited to any specific combination of hardware and software.

[0050] Although the specific embodiments of the present application are described above in combination with the drawings, it is not a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications or variations made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. A method for shallow surface geological exploration in urban areas, characterized in that, include: Ground physical exploration was conducted in the area to be surveyed using a combined electromagnetic and seismic emission detection mode to identify shallow surface geological anomaly areas. Using shallow surface geological anomaly areas as prior information, the borehole physical exploration was carried out by fusion of cross-hole electromagnetic wave CT and cross-hole elastic wave CT to obtain the morphological characteristics of the underground structure. The results of cross-hole electromagnetic wave CT and cross-hole elastic wave CT were fused by using a weighted average method and assigning corresponding weights according to the importance of different geological features. Using the morphological characteristics of underground structures obtained from borehole physical exploration as prior information, geological drilling is carried out using borehole logging technology and laser scanning to identify underground anomalies and assess their size, shape, and location. The identification results obtained from geological drilling are used as posterior information for borehole physical exploration, which in turn guides the process of borehole physical exploration. The results obtained from borehole physical exploration are used as posterior information for ground physical exploration, which in turn guides the ground geophysical exploration process. The morphological characteristics of the adverse geological structures in the survey area are compared with the results of ground physical exploration to determine the scale and location information of the adverse geological bodies. This information is used as a post-hoc information correction for the selection and interpretation criteria of data processing parameters in ground physical exploration. Repeat the above steps until all areas to be explored have been explored.

2. The urban shallow surface geological exploration method as described in claim 1, characterized in that, Based on the surface environment characteristics of the area to be surveyed, seismic wave reflection method, micro-motion exploration, high-density resistivity and transient electromagnetic method were used for detection.

3. The urban shallow surface geological exploration method as described in claim 1, characterized in that, Based on the geological anomaly areas obtained from the combined electro-seismic detection, and taking the spatial distribution and scale of the geological anomaly areas as a benchmark, a detection scheme for borehole physical detection is designed; wherein, the spacing between measuring points set at the boundary of the anomaly area should be smaller than the spacing between measuring points set in the uniform area of ​​the anomaly area.

4. The urban shallow surface geological exploration method as described in claim 3, characterized in that, A method combining cross-hole electromagnetic wave CT and cross-hole elastic wave CT was used for in-hole physical exploration. Geological interpretation was performed on the close-range images obtained by the fusion of cross-hole electromagnetic wave CT and cross-hole elastic wave CT. Based on the range of relatively low-velocity areas in the wave velocity map, the morphological characteristics of adverse geological structures in the survey area were determined.

5. The urban shallow surface geological exploration method as described in claim 1, characterized in that, During the drilling process in geological drilling, rock and soil samples are taken along the borehole depth to determine the physical and mechanical properties of the rocks and soil. The distance from the laser emission source to the unfavorable geological body is determined by laser scanning in the borehole, and the morphological characteristics of the unfavorable geological body are obtained.

6. The urban shallow surface geological exploration method as described in claim 1, characterized in that, Based on the geological anomaly areas obtained from the electro-seismic joint detection mode, the spatial location and scale of the geological anomaly areas are determined. Based on the determined spatial location and scale of the geological anomaly areas, the borehole location and depth information for in-hole physical detection are determined.

7. The urban shallow surface geological exploration method as described in claim 1, characterized in that, Based on the spatial location of the geological anomaly determined by ground physical survey and borehole physical survey, drilling points should be set up to fully cover the geological anomaly. Based on the depth range of the geological anomaly determined by ground physical survey and borehole physical survey, the minimum drilling depth should be determined, and the drilling should at least penetrate the bottom of the anomaly.

8. The urban shallow surface geological exploration method as described in claim 2, characterized in that, The data collected by ground physical exploration are denoised and corrected, then imaged and interpreted to obtain geological information of the exploration area and identify shallow surface geological anomaly areas.

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