A construction site geological three-dimensional model construction method and system

Abstract

This invention relates to the field of 3D modeling technology, specifically disclosing a method for constructing a 3D geological model of a construction site, comprising the following steps: S1: determining the borehole spacing based on the signal-to-noise ratio and arranging the borehole points into an equilateral triangular grid; S2: setting the CT detection layer depth according to a geometric progression; S3: synchronously lowering the probe to the same CT detection layer, with each borehole sending pulses to neighboring boreholes; S4: calculating the wave velocity based on the pulse arrival time and calculating the medium wave velocity; S5: performing geological pattern discrimination based on the medium wave velocity and thickness ratio. This invention employs an equilateral triangular borehole layout and a geometrically proportioned CT detection layer, combined with multi-directional pulse measurement, to obtain the lateral wave velocity differences between boreholes, breaking through the traditional vertical limitations. Furthermore, based on the medium wave velocity and thickness ratio, it automatically identifies three geological structures: gently continuing, overturning and thinning, and pinching out, compensating for the lack of lateral information in the boreholes.

Description

Technical Field

[0001] This invention relates to the field of 3D modeling technology, specifically to a method and system for constructing a 3D geological model of a construction site. Background Technology

[0002] In 3D geological modeling, boreholes are the most direct means of obtaining subsurface information, with a vertical resolution down to the decimeter level, capable of recording stratigraphic boundaries, lithological variations, and in-situ test parameters for every meter. However, the information structure of boreholes is inherently single-point vertical, only able to answer what lies beneath that point, but unable to directly provide the horizontal variation patterns of the strata. Whether the strata between two boreholes are gently continuous, dipping and thinning, or pinching out, the borehole data itself cannot perceive this. In contrast, the core task of 3D geological models is to construct continuous geological bodies, in which lateral correlation and inference play a dominant role. The extension of stratigraphic interfaces, the transition of lithological facies, and the tracing of tectonic faults all rely on the inference of unknown areas between boreholes. This functional mismatch between high vertical resolution and zero lateral information poses a fundamental challenge to current modeling methods in site scenarios with sparse boreholes. Traditional interpolation algorithms are forced to fill lateral gaps based on smoothness assumptions, easily generating smooth but erroneous stratigraphic connections, thus underestimating or completely omitting important discontinuous geological phenomena such as pinch-outs and lenses. Therefore, there is an urgent need for a method that can compensate for the lack of lateral information in boreholes, in order to solve the current dilemma of lateral inference being constrained by data bottlenecks in modeling. Summary of the Invention

[0003] The purpose of this invention is to provide a method and system for constructing a three-dimensional geological model of a construction site, thereby solving the above-mentioned technical problems.

[0004] The objective of this invention can be achieved through the following technical solutions: A method for constructing a three-dimensional geological model of a construction site includes the following steps: S1: Calculate the borehole spacing L based on the current geological conditions of the construction site, and arrange the borehole points in an equilateral triangle grid. The horizontal distance between any two adjacent boreholes in the equilateral triangle grid is equal to L. S2: A CT detection layer is set in each borehole along the depth direction, and the depth of the CT detection layer is taken in a geometric sequence. S3: A retractable transceiver probe is built into each borehole, allowing all borehole probes to remain at the same CT detection layer; Select any borehole as the transmitting hole, and control the transceiver probe in the transmitting hole to transmit TTL trigger pulses in the direction of the six nearest adjacent boreholes. After the transmission is completed, switch to the next transmitting hole and repeat the above steps until all transmitting holes have completed the transmission. S4: If the horizontal distance between boreholes A and B is equal to L, then boreholes A and B are neighbors. Calculate the medium wave velocity v of borehole A in the first CT detection layer. A Repeat this step to calculate the medium wave velocity of the remaining CT detection layer in borehole A, and complete the calculation of the remaining boreholes; S5: Geological model discrimination based on medium wave velocity, including: Obtain the medium wave velocity v of borehole B B If the medium wave velocities of neighboring boreholes A and B satisfy... If the condition is satisfied for all neighbors of borehole A, then it is marked as "smooth continuation", where v B，A This represents the wave velocity at which the TTL trigger pulse emitted from borehole B arrives at borehole A. Obtain the medium wave velocity v of the i-th CT detection layer in borehole A A_i With the medium wave velocity v of the j-th layer A_j ,like This represents a stratigraphic unit, and the depth Z of the top surface of that stratigraphic unit is obtained. top and bottom depth Z bot Calculate the thickness h of the formation unit at borehole A. A =Z bot -Z top Obtain the thickness h of borehole B. B Calculate the thickness ratio η = (h A -h B ) / h A If 20%≤η≤80%, then it is recorded as a candidate borehole. If the wave velocity v of the candidate borehole is... B，A If the lithology is between vA and vB and exhibits a monotonic change, it is labeled as "gradual lithological change, thinning upon overturning," and the dip angle is... Among them, Z top，A and Z top，B These represent the top surface depths of boreholes A and B, respectively. At CT detection layer k in boreholes A and B, if the formation characteristics are satisfied... The wave velocity of borehole A stabilizes at v in the adjacent CT detection layers k-1 and k+1. A ±20%, and borehole B does not have a continuous CT detection layer, its wave velocity is stable at v B ±20%, at which point it is marked as "expiration".

[0005] As a further aspect of the present invention: in step S1, calculating the borehole spacing L based on the current site geology includes: Set the spacing R = R0 + λ × r, where R0 represents the preset initial spacing, λ represents the preset gradient λ = 0, 1, ..., and r represents the preset unit distance. Instruct the transmitting probe to transmit a preset signal to the receiving probe and calculate the signal-to-noise ratio (SNR). Take the maximum spacing where the SNR is not lower than the preset threshold as the value of the borehole spacing L.

[0006] As a further aspect of the present invention, it is ensured that the transmitting probe and the receiving probe are always at the same depth.

[0007] As a further aspect of the present invention: in step S2, a CT detection layer is provided along the depth direction in each borehole, and the depth of the CT detection layer specifically includes values ​​taken in a geometric sequence: The unit depth d is preset, and the depth of the first layer is set to d. The depth of each layer is doubled until the drilling design depth is reached, and the drilling design depth is used as the last layer.

[0008] As a further aspect of the present invention: in step S3, the medium wave velocity v of borehole A in the first CT detection layer is calculated. A The methods include: Obtain the time t when the TTL trigger pulse emitted from borehole B arrives at borehole A. A Calculate wave speed v B，A =L / t A Similarly, calculate the wave velocity of the remaining neighboring TTL trigger pulses arriving at A, and calculate the average wave velocity of borehole A. I represents the number of neighbors of borehole A, v i The average wave velocity v represents the wave velocity of the TTL trigger pulse emitted by the i-th neighbor arriving at A. avg Let v be the medium wave velocity at the depth of borehole A. A .

[0009] As a further aspect of the present invention: in step S1, it is ensured that the number of holes in the equilateral triangular grid is greater than or equal to 7, and that there is at least one regular hexagon in the equilateral triangular grid consisting of a central hole and six adjacent holes.

[0010] As a further aspect of the present invention: in step S1, when drilling, ensure that the drilling direction is perpendicular to the horizontal plane.

[0011] A system for constructing a three-dimensional geological model of a construction site, comprising: Distance module: Calculate the borehole spacing L based on the current site geology, and arrange the borehole points in an equilateral triangle grid, wherein the horizontal distance between any two adjacent boreholes in the equilateral triangle grid is equal to L; Depth module: A CT detection layer is set along the depth direction in each borehole, and the depth of the CT detection layer is taken in a geometric sequence; Transmitting module: A retractable transceiver probe is built into each borehole, allowing all borehole probes to remain at the same CT detection layer; Select any borehole as the transmitting hole, and control the transceiver probe in the transmitting hole to transmit TTL trigger pulses in the direction of the six nearest adjacent boreholes. After the transmission is completed, switch to the next transmitting hole and repeat the above steps until all transmitting holes have completed the transmission. Medium module: If the horizontal distance between boreholes A and B is equal to L, then boreholes A and B are neighbors. Calculate the medium wave velocity v of borehole A in the first CT detection layer. A Repeat this step to calculate the medium wave velocity of the remaining CT detection layer in borehole A, and complete the calculation of the remaining boreholes; Analysis module: Geological pattern discrimination based on medium wave velocity, including: Obtain the medium wave velocity v of borehole B B If the medium wave velocities of neighboring boreholes A and B satisfy... If the condition is satisfied for all neighbors of borehole A, then it is marked as "smooth continuation", where v B，A This represents the wave velocity at which the TTL trigger pulse emitted from borehole B arrives at borehole A. Obtain the medium wave velocity v of the i-th CT detection layer in borehole A A_i With the medium wave velocity v of the j-th layer A_j ,like This represents a stratigraphic unit, and the depth Z of the top surface of that stratigraphic unit is obtained. top and bottom depth Z bot Calculate the thickness h of the formation unit at borehole A. A =Z bot -Z top Obtain the thickness h of borehole B. B Calculate the thickness ratio η = (h A -h B ) / h A If 20%≤η≤80%, then it is recorded as a candidate borehole. If the wave velocity v of the candidate borehole is... B，A If the lithology is between vA and vB and exhibits a monotonic change, it is labeled as "gradual lithological change, thinning upon overturning," and the dip angle is... Among them, Z top，A and Z top，B These represent the top surface depths of boreholes A and B, respectively. At CT detection layer k in boreholes A and B, if the formation characteristics are satisfied... The wave velocity of borehole A stabilizes at v in the adjacent CT detection layers k-1 and k+1. A ±20%, and borehole B does not have a continuous CT detection layer, its wave velocity is stable at v B ±20%, at which point it is marked as "expiration".

[0012] The beneficial effects of this invention are as follows: By using an equilateral triangular grid of boreholes and a geometrically ordered depth for CT detection layers, combined with the synchronous raising and lowering of the transceiver probes in all boreholes and multi-directional TTL trigger pulse measurements, the medium wave velocity at different depths in each borehole can be obtained. This overcomes the limitation of traditional boreholes providing only vertical single-point information, directly acquiring the lateral wave velocity differences between boreholes, providing a data foundation for determining the lateral variation patterns of strata. Furthermore, based on the geological model discrimination rules established by the wave velocity ratio and thickness ratio, it can automatically identify three typical lateral geological structures: gently continuous, overturned thinning, and pinch-out. The pinch-out criterion, through stable comparison of wave velocities between upper and lower layers, effectively avoids the defect of traditional interpolation algorithms that incorrectly connect discontinuous strata due to smoothing assumptions. Attached Figure Description

[0013] The invention will now be further described with reference to the accompanying drawings.

[0014] Figure 1 This is a schematic diagram of the structure of a method for constructing a three-dimensional geological model of a construction site according to the present invention; Figure 2 This is a flowchart illustrating a method for constructing a three-dimensional geological model of a construction site according to the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Please see Figure 1 As shown, this invention provides a method for constructing a three-dimensional geological model of a construction site, comprising the following steps: S1: Calculate the borehole spacing L based on the current geological conditions of the construction site, and arrange the borehole points in an equilateral triangle grid. The horizontal distance between any two adjacent boreholes in the equilateral triangle grid is equal to L. S2: A CT detection layer is set in each borehole along the depth direction, and the depth of the CT detection layer is taken in a geometric sequence. S3: A retractable transceiver probe is built into each borehole, allowing all borehole probes to remain at the same CT detection layer; Select any borehole as the transmitting hole, and control the transceiver probe in the transmitting hole to transmit TTL trigger pulses in the direction of the six nearest adjacent boreholes. After the transmission is completed, switch to the next transmitting hole and repeat the above steps until all transmitting holes have completed the transmission. S4: If the horizontal distance between boreholes A and B is equal to L, then boreholes A and B are neighbors. Calculate the medium wave velocity v of borehole A in the first CT detection layer. A Repeat this step to calculate the medium wave velocity of the remaining CT detection layer in borehole A, and complete the calculation of the remaining boreholes; S5: Geological model discrimination based on medium wave velocity, including: Obtain the medium wave velocity v of borehole B B If the medium wave velocities of neighboring boreholes A and B satisfy... If the condition is satisfied for all neighbors of borehole A, then it is marked as "smooth continuation", where v B，A This represents the wave velocity at which the TTL trigger pulse emitted from borehole B arrives at borehole A. Obtain the medium wave velocity v of the i-th CT detection layer in borehole A A_i With the medium wave velocity v of the j-th layer A_j ,like This represents a stratigraphic unit, and the depth Z of the top surface of that stratigraphic unit is obtained. top and bottom depth Z bot Calculate the thickness h of the formation unit at borehole A. A =Z bot -Z top Obtain the thickness h of borehole B. B Calculate the thickness ratio η = (h A -h B ) / h A If 20%≤η≤80%, then it is recorded as a candidate borehole. If the wave velocity v of the candidate borehole is... B，A If the lithology is between vA and vB and exhibits a monotonic change, it is labeled as "gradual lithological change, thinning upon overturning," and the dip angle is... Among them, Z top，A and Z top，B These represent the top surface depths of boreholes A and B, respectively. At CT detection layer k in boreholes A and B, if the formation characteristics are satisfied... The wave velocity of borehole A stabilizes at v in the adjacent CT detection layers k-1 and k+1. A ±20%, and borehole B does not have a continuous CT detection layer, its wave velocity is stable at v B ±20%, at which point it is marked as "expiration".

[0017] It should be noted that, based on the site's geological conditions, the maximum effective borehole spacing L was determined through signal-to-noise ratio testing. The boreholes were then arranged in an equilateral triangular grid, with adjacent boreholes spaced at L intervals, and the borehole direction perpendicular to the horizontal plane. Next, CT detection layers were installed along the depth of each borehole in a geometric progression until the designed depth was reached. Then, a retractable transceiver probe was installed in each borehole, with all probes synchronously positioned at the same detection layer. Each borehole was sequentially selected as a transmitting borehole, emitting TTL pulses in the directions of six adjacent boreholes, and the propagation time was recorded. Subsequently, the medium wave velocity of each borehole at each detection layer was calculated based on the adjacent borehole spacing L and the pulse propagation time. Finally, geological patterns are determined based on wave velocity. If the relative difference in wave velocity between adjacent boreholes within the same layer is ≤5% and all neighboring boreholes meet this condition, it is classified as a gradual continuation. If the difference in wave velocity between different layers within the same borehole is greater than 20%, stratigraphic units are defined, and unit thicknesses are calculated. When the thickness ratio between adjacent boreholes is between 20% and 80% and the wave velocity changes monotonically, it is classified as a gradual lithological change or overturning thinning, and the dip angle is calculated. If the difference in wave velocity between adjacent boreholes within the same layer is greater than 30%, and the wave velocities of the upper and lower layers of the transmitting borehole are stable, while the receiving borehole has no continuous stable wave velocity layer, it is classified as pinch-out. This method can obtain lateral geological variation information using only a small number of boreholes and effectively identify discontinuous phenomena such as pinch-out. Figure 2 Condition 1 refers to the wave velocity difference between adjacent layers being ≤5%, condition 2 refers to the wave velocity difference within a layer being >20% and the thickness ratio being in the range [20%, 80%] and the wave velocity being monotonic, and condition 3 refers to the wave velocity difference within a layer being >30% and the upper and lower layers being stable while there is no continuous layer between them.

[0018] In another preferred embodiment of the present invention, calculating the borehole spacing L based on the current site geology includes: Set the spacing R = R0 + λ × r, where R0 represents the preset initial spacing, λ represents the preset gradient λ = 0, 1, ..., and r represents the preset unit distance. Instruct the transmitting probe to transmit a preset signal to the receiving probe and calculate the signal-to-noise ratio (SNR). Take the maximum spacing where the SNR is not lower than the preset threshold as the value of the borehole spacing L.

[0019] It is worth noting that, unlike the usual approach of pursuing the maximum spacing to save on the number of boreholes, this scheme starts with the minimum effective spacing, gradually increases the spacing, and calculates the signal-to-noise ratio (SNR) in real time, taking the minimum spacing with an SNR not lower than a preset threshold as L. The advantages of this approach are: firstly, it minimizes the borehole spacing while ensuring signal recognition quality, thereby obtaining denser and more continuous wave velocity sampling data, providing higher spatial resolution for subsequent lateral formation discrimination; secondly, the minimum spacing principle effectively avoids problems such as decreased SNR, pulse attenuation, or enhanced environmental interference caused by excessive spacing, ensuring stable and reliable wave velocity measurement results between each borehole; and thirdly, this method automatically adapts to different geological conditions through gradient incremental search, automatically using a smaller L for complex formations with strong signal attenuation, while appropriately widening L for homogeneous formations, ensuring data validity while avoiding waste caused by blindly increasing density.

[0020] In another preferred embodiment of the invention, it is ensured that the transmitting probe and the receiving probe are always at the same depth.

[0021] Understandably, the wave velocity in a medium can vary significantly with depth. If the probe depths are inconsistent, the measured propagation time will contain mixed information from strata at different depths, failing to accurately reflect the lateral wave velocity differences within the same CT-detected layer. A uniform depth ensures that all measurement results strictly correspond to the predetermined stratigraphic interface, avoiding stratigraphic unit misalignment caused by depth offsets. This provides a reliable wave velocity benchmark for subsequent determinations of smooth continuation and pinch-out.

[0022] In another preferred embodiment of the present invention, a CT detection layer is provided along the depth direction in each borehole, and the depth of the CT detection layer specifically includes values ​​taken in a geometric sequence: The unit depth d is preset, and the depth of the first layer is set to d. The depth of each layer is doubled until the drilling design depth is reached, and the drilling design depth is used as the last layer.

[0023] It is important to note that shallow strata typically exhibit more frequent geological changes and receive greater engineering attention. Proportional densification in the first few layers provides high-resolution sampling, capturing lithological interfaces and gradual changes in wave velocity. Deep strata are relatively stable, and appropriately reducing sampling density can decrease redundant detection and improve overall efficiency. Secondly, this non-equidistant stratification method significantly reduces the total number of detection layers while ensuring data integrity in critical areas, thereby shortening the probe traverse and pulse emission cycle time, reducing power consumption and equipment wear. Finally, using the designed drilling depth as the final layer ensures that no bottom hole information is missed.

[0024] In another preferred embodiment of the present invention, the medium wave velocity v of borehole A in the first CT detection layer is calculated. A The methods include: Obtain the time t when the TTL trigger pulse emitted from borehole B arrives at borehole A. A Calculate wave speed v B，A =L / t A Similarly, calculate the wave velocity of the remaining neighboring TTL trigger pulses arriving at A, and calculate the average wave velocity of borehole A. I represents the number of neighbors of borehole A, v i The average wave velocity v represents the wave velocity of the TTL trigger pulse emitted by the i-th neighbor arriving at A. avg Let v be the medium wave velocity at the depth of borehole A. A .

[0025] It should be noted that by taking advantage of the fact that each borehole in an equilateral triangular grid typically has 6 adjacent boreholes, pulse propagation time can be obtained from multiple directions and wave velocity can be calculated separately. The average value can then be taken to effectively offset random deviations caused by local medium inhomogeneity, measurement errors, or pulse interference in individual directions. Moreover, the average wave velocity represents the overall response characteristics of the strata around borehole A, which is more representative than the measurement value in a single direction, and provides benchmark data for subsequent geological model discrimination.

[0026] In another preferred embodiment of the present invention, it is ensured that the number of holes in the equilateral triangular grid is greater than or equal to 7, and that there is at least one regular hexagon in the equilateral triangular grid consisting of a central hole and six adjacent holes.

[0027] Understandably, this preferred scheme requires at least seven boreholes forming at least one regular hexagonal structure. This is significant in ensuring the integrity and data symmetry of the detection system. In the equilateral triangular grid, the central borehole has six equidistant neighboring boreholes, corresponding precisely to the six emission directions. This forms the geometric basis for the six-directional TTL pulse emission in step S3. If the number of boreholes is insufficient or cannot form a regular hexagon, the number of neighbors for the edge boreholes will be less than six, resulting in insufficient samples during wave velocity averaging and reduced measurement reliability. Furthermore, the regular hexagonal cells can be repeatedly spliced ​​and extended throughout the entire site, ensuring that each internal borehole has complete neighbor information.

[0028] In another preferred embodiment of the present invention, when drilling, it is ensured that the drilling direction is perpendicular to the horizontal plane.

[0029] It is worth noting that ensuring the boreholes are perpendicular to the horizontal plane guarantees that the distance between adjacent boreholes is equal to L, eliminating the need for slant distance correction in wave velocity calculation; at the same time, it simplifies data processing by ensuring that each borehole corresponds to the same CT detection layer at the same altitude.

[0030] A system for constructing a three-dimensional geological model of a construction site, comprising: Distance module: Calculate the borehole spacing L based on the current site geology, and arrange the borehole points in an equilateral triangle grid, wherein the horizontal distance between any two adjacent boreholes in the equilateral triangle grid is equal to L; Depth module: A CT detection layer is set along the depth direction in each borehole, and the depth of the CT detection layer is taken in a geometric sequence; Transmitting module: A retractable transceiver probe is built into each borehole, allowing all borehole probes to remain at the same CT detection layer; Select any borehole as the transmitting hole, and control the transceiver probe in the transmitting hole to transmit TTL trigger pulses in the direction of the six nearest adjacent boreholes. After the transmission is completed, switch to the next transmitting hole and repeat the above steps until all transmitting holes have completed the transmission. Medium module: If the horizontal distance between boreholes A and B is equal to L, then boreholes A and B are neighbors. Calculate the medium wave velocity v of borehole A in the first CT detection layer. A Repeat this step to calculate the medium wave velocity of the remaining CT detection layer in borehole A, and complete the calculation of the remaining boreholes; Analysis module: Geological pattern discrimination based on medium wave velocity, including: Obtain the medium wave velocity v of borehole B B If the medium wave velocities of neighboring boreholes A and B satisfy... If the condition is satisfied for all neighbors of borehole A, then it is marked as "smooth continuation", where v B，A This represents the wave velocity at which the TTL trigger pulse emitted from borehole B arrives at borehole A. Obtain the medium wave velocity v of the i-th CT detection layer in borehole A A_i With the medium wave velocity v of the j-th layer A_j ,like This represents a stratigraphic unit, and the depth Z of the top surface of that stratigraphic unit is obtained. top and bottom depth Z bot Calculate the thickness h of the formation unit at borehole A. A =Z bot -Z top Obtain the thickness h of borehole B. B Calculate the thickness ratio η = (h A -h B ) / h A If 20%≤η≤80%, then it is recorded as a candidate borehole. If the wave velocity v of the candidate borehole is... B，A If the lithology is between vA and vB and exhibits a monotonic change, it is labeled as "gradual lithological change, thinning upon overturning," and the dip angle is... Among them, Z top，A and Z top，B These represent the top surface depths of boreholes A and B, respectively. At CT detection layer k in boreholes A and B, if the formation characteristics are satisfied... The wave velocity of borehole A stabilizes at v in the adjacent CT detection layers k-1 and k+1. A ±20%, and borehole B does not have a continuous CT detection layer, its wave velocity is stable at v B ±20%, at which point it is marked as "expiration".

[0031] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for constructing a three-dimensional geological model of a construction site, characterized in that, Includes the following steps: S1: Calculate the borehole spacing L based on the current geological conditions of the construction site, and arrange the borehole points in an equilateral triangle grid. The horizontal distance between any two adjacent boreholes in the equilateral triangle grid is equal to L. S2: A CT detection layer is set in each borehole along the depth direction, and the depth of the CT detection layer is taken in a geometric sequence. S3: A retractable transceiver probe is built into each borehole, allowing all borehole probes to remain at the same CT detection layer; Select any borehole as the transmitting hole, and control the transceiver probe in the transmitting hole to transmit TTL trigger pulses in the direction of the six nearest adjacent boreholes. After the transmission is completed, switch to the next transmitting hole and repeat the above steps until all transmitting holes have completed the transmission. S4: If the horizontal distance between boreholes A and B is equal to L, then boreholes A and B are neighbors. Calculate the medium wave velocity v of borehole A in the first CT detection layer. A Repeat this step to calculate the medium wave velocity of the remaining CT detection layer in borehole A, and complete the calculation of the remaining boreholes; S5: Geological model discrimination based on medium wave velocity, including: Obtain the medium wave velocity v of borehole B B If the medium wave velocities of neighboring boreholes A and B satisfy... If the condition is satisfied for all neighbors of borehole A, then it is marked as "smooth continuation", where v B，A This represents the wave velocity at which the TTL trigger pulse emitted from borehole B arrives at borehole A. Obtain the medium wave velocity v of the i-th CT detection layer in borehole A A_i With the medium wave velocity v of the j-th layer A_j ,like This represents a stratigraphic unit, and the depth Z of the top surface of that stratigraphic unit is obtained. top and bottom depth Z bot Calculate the thickness h of the formation unit at borehole A. A =Z bot -Z top Obtain the thickness h of borehole B. B Calculate the thickness ratio η = (h A -h B ) / h A If 20%≤η≤80%, then it is recorded as a candidate borehole. If the wave velocity v of the candidate borehole is... B，A If the lithology is between vA and vB and exhibits a monotonic change, it is labeled as "gradual lithological change, thinning upon overturning," and the dip angle is... Among them, Z top，A and Z top，B These represent the top surface depths of boreholes A and B, respectively. At CT detection layer k in boreholes A and B, if the formation characteristics are satisfied... The wave velocity of borehole A stabilizes at v in the adjacent CT detection layers k-1 and k+1. A ±20%, and borehole B does not have a continuous CT detection layer, its wave velocity is stable at v B ±20%, at which point it is marked as "expiration".

2. The method for constructing a three-dimensional geological model of a construction site according to claim 1, characterized in that, In step S1, calculating the borehole spacing L based on the current site geology includes: Set the spacing R = R0 + λ × r, where R0 represents the preset initial spacing, λ represents the preset gradient λ = 0, 1, ..., and r represents the preset unit distance. Instruct the transmitting probe to transmit a preset signal to the receiving probe and calculate the signal-to-noise ratio (SNR). Take the maximum spacing where the SNR is not lower than the preset threshold as the value of the borehole spacing L.

3. The method for constructing a three-dimensional geological model of a construction site according to claim 2, characterized in that, Ensure that the transmitting and receiving probes are always at the same depth.

4. The method for constructing a three-dimensional geological model of a construction site according to claim 1, characterized in that, In step S2, a CT detection layer is installed along the depth direction in each borehole. The depth of the CT detection layer is specifically determined by a geometric series of values: The unit depth d is preset, and the depth of the first layer is set to d. The depth of each layer is doubled until the drilling design depth is reached, and the drilling design depth is used as the last layer.

5. The method for constructing a three-dimensional geological model of a construction site according to claim 1, characterized in that, In step S4, the medium wave velocity v of borehole A in the first CT detection layer is calculated. A The methods include: Obtain the time t when the TTL trigger pulse emitted from borehole B arrives at borehole A. A Calculate wave speed v B，A =L / t A Similarly, calculate the wave velocity of the remaining neighboring TTL trigger pulses arriving at A, and calculate the average wave velocity of borehole A. I represents the number of neighbors of borehole A, v i The average wave velocity v represents the wave velocity of the TTL trigger pulse emitted by the i-th neighbor arriving at A. avg Let v be the medium wave velocity at the depth of borehole A. A .

6. The method for constructing a three-dimensional geological model of a construction site according to claim 1, characterized in that, In step S1, it is ensured that the number of holes in the equilateral triangle grid is greater than or equal to 7, and that there is at least one regular hexagon in the equilateral triangle grid consisting of a central hole and six adjacent holes.

7. The method for constructing a three-dimensional geological model of a construction site according to claim 1, characterized in that, In step S1, when drilling, ensure that the drilling direction is perpendicular to the horizontal plane.

8. A system for constructing a three-dimensional geological model of a construction site, characterized in that, include: Distance module: Calculate the borehole spacing L based on the current site geology, and arrange the borehole points in an equilateral triangle grid, wherein the horizontal distance between any two adjacent boreholes in the equilateral triangle grid is equal to L; Depth module: A CT detection layer is set along the depth direction in each borehole, and the depth of the CT detection layer is taken in a geometric sequence; Transmitting module: A retractable transceiver probe is built into each borehole, allowing all borehole probes to remain at the same CT detection layer; Select any borehole as the transmitting hole, and control the transceiver probe in the transmitting hole to transmit TTL trigger pulses in the direction of the six nearest adjacent boreholes. After the transmission is completed, switch to the next transmitting hole and repeat the above steps until all transmitting holes have completed the transmission. Medium module: If the horizontal distance between boreholes A and B is equal to L, then boreholes A and B are neighbors. Calculate the medium wave velocity v of borehole A in the first CT detection layer. A Repeat this step to calculate the medium wave velocity of the remaining CT detection layer in borehole A, and complete the calculation of the remaining boreholes; Analysis module: Geological pattern discrimination based on medium wave velocity, including: Obtain the medium wave velocity v of borehole B B If the medium wave velocities of neighboring boreholes A and B satisfy... If the condition is satisfied for all neighbors of borehole A, then it is marked as "smooth continuation", where v B，A This represents the wave velocity at which the TTL trigger pulse emitted from borehole B arrives at borehole A. Obtain the medium wave velocity v of the i-th CT detection layer in borehole A A_i With the medium wave velocity v of the j-th layer A_j ,like This represents a stratigraphic unit, and the depth Z of the top surface of that stratigraphic unit is obtained. top and bottom depth Z bot Calculate the thickness h of the formation unit at borehole A. A =Z bot -Z top Obtain the thickness h of borehole B. B Calculate the thickness ratio η = (h A -h B ) / h A If 20%≤η≤80%, then it is recorded as a candidate borehole. If the wave velocity v of the candidate borehole is... B，A If the lithology is between vA and vB and exhibits a monotonic change, it is labeled as "gradual lithological change, thinning upon overturning," and the dip angle is... Among them, Z top，A and Z top，B These represent the top surface depths of boreholes A and B, respectively. At CT detection layer k in boreholes A and B, if the formation characteristics are satisfied... The wave velocity of borehole A stabilizes at v in the adjacent CT detection layers k-1 and k+1. A ±20%, and borehole B does not have a continuous CT detection layer, its wave velocity is stable at v B ±20%, at which point it is marked as "expiration".

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