Accurate tunnel construction crack water detection method based on advanced parallel adit

Abstract

The invention discloses a tunnel construction crack water accurate detection method based on advanced parallel adit. During tunnel construction in a hard mountainous area, the geological environment in front of a main tunnel face is complex and changeable. The method comprises the steps that the position of a low-resistance area of a to-be-excavated area of a high-risk tunnel main hole is determined; the method comprises the following steps: respectively measuring multiple groups of fracture structural surfaces in exposed rock masses of an advanced parallel adit and a main tunnel face of a tunnel, and screening out dominant fracture structural surfaces from the multiple groups of fracture structural surfaces; comparing the occurrence information of the dominant fracture structural surfaces of the advance parallel adit and the tunnel main hole tunnel face, when the differences between the trends and the inclination angles of the dominant fracture structural surfaces of the advance parallel adit and the tunnel main hole tunnel face are smaller than acute angles, averaging the trends and the inclination angles, and taking the averaged trends and inclination angles as the occurrence information of the penetrating fracture structural surfaces; and the fracture water gushing position of the to-be-excavated area of the main tunnel is calculated. The problems that high-risk tunnel advanced parallel adit utilization is insufficient, and prediction of the fracture water gushing position of the to-be-excavated area of the main tunnel of the tunnel is inaccurate are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tunnel advanced geological prediction, and particularly relates to a tunnel construction fissure water accurate detection method based on an advanced flat pilot. BACKGROUND

[0002] As an electromagnetic induction method, transient electromagnetic method has the characteristics of sensitive reflection to low-resistance water-filled fractured zone, and is a short-distance effective prediction method for detecting underground water. The low-resistance zone is often the water distribution area, and the effective detection distance is about 60 meters. In tunnel construction, the transient electromagnetic method is usually applied to the tunnel face. The application determines the water-bearing conditions of the tunnel to be excavated area and the surrounding rock mass through the lateral judgment of the advanced flat pilot.

[0003] In the construction of a tunnel in a dangerous mountainous area, the geological environment in front of the tunnel face is complex and variable, and there is often fissure water in the bedrock. In construction, a parallel pilot tunnel (referred to as an advanced flat pilot) with a small cross section is excavated about 10-30 meters away from the tunnel to reveal unknown water gushing risks in advance. Compared with geophysical prospecting methods, the method is more intuitive and accurate. However, the advanced flat pilot is not fully utilized at present, and the water-bearing conditions of the tunnel are predicted by parallel deduction at the same distance.

[0004] Fissure water in bedrock is often present in the fissure structure surface, and a water body connection space is formed in the fissure structure surface. From the perspective of the geological gestation law of the fissure structure surface, the spatial deduction of the advanced flat pilot towards the tunnel face can accurately predict the water-bearing conditions of the tunnel to be excavated area, which is of great significance for the prediction and prevention of water gushing risks in tunnel excavation and construction. SUMMARY

[0005] In order to make up for the shortcomings of the prior art, the application provides a tunnel construction fissure water accurate detection method based on an advanced flat pilot, which starts from the geological gestation law of the fissure structure surface to solve the problems of insufficient utilization of the advanced flat pilot in high-risk tunnels and inaccurate prediction of fissure water gushing positions in the tunnel to be excavated area.

[0006] In order to achieve the above purpose, the technical scheme adopted by the application is as follows: A tunnel construction fissure water accurate detection method based on an advanced flat pilot, comprising the following steps: S1: determining the low-resistance zone position of the tunnel to be excavated area in a high-risk tunnel; S2: measuring a plurality of fissure structure surfaces in the exposed rock mass of the advanced flat pilot and the tunnel face, respectively, and selecting an advantage fissure structure surface from the plurality of fissure structure surfaces; S3: compare the advantage fissure structure surface occurrence information of the tunnel advance guide and the tunnel face, if the difference between the advantage fissure structure surface occurrence of the tunnel advance guide and the tunnel face is less than an acute angle, take the average of the occurrence of the tunnel advance guide and the tunnel face as the occurrence of the through fissure structure surface; S4: calculate the fissure water gushing position of the tunnel face to be excavated according to the low resistance zone position measured in S1.

[0007] Further, the specific method of the step S1 is: S1-1: use the transient electromagnetic method to detect the low resistance zone on the side wall of the tunnel advance guide facing the tunnel face to be excavated; S1-2: determine the position of the low resistance zone according to the spatial distribution and change of the resistivity analyzed from the transient electromagnetic detection data.

[0008] Further, the specific method of the step S2 is: S2-1: measure multiple sets of fissure structure surfaces on the exposed bedrock of the tunnel advance guide face and record the occurrence information; S2-2: measure multiple sets of fissure structure surfaces on the exposed bedrock of the tunnel face and record the occurrence information; S2-3: compare the multiple sets of fissure structure surfaces in S2-1 and S2-2 according to the on-site face conditions, and select 2 sets of fissure structure surfaces as the advantage fissure structure surfaces according to the length selection principle, and the occurrence information of the first and second advantage fissure structure surfaces of the tunnel advance guide are recorded as Ja and Jb respectively, and the occurrence information of the first and second advantage fissure structure surfaces of the tunnel face are recorded as Ja' and Jb' respectively.

[0009] Further, the occurrence information includes the strike and dip of the fissure structure surface.

[0010] Further, the specific method of the step S3 is: Step S3-1: compare the advantage fissure structure surface occurrence information of the tunnel face and the tunnel advance guide in turn, i.e. Ja' and Ja, Ja' and Jb, Jb' and Ja, and Jb' and Jb; Step S3-2: if the difference between the advantage fissure structure surface occurrence of the tunnel face and the tunnel advance guide is less than an acute angle, name the corresponding occurrence of the tunnel advance guide as J1, and the corresponding occurrence of the tunnel face as J1', take the average of the strike of J1 and the strike of J1' as the strike of the through fissure structure surface occurrence J1", and take the average of the dip of J1 and the dip of J1' as the dip of the through fissure structure surface occurrence J1"; Step S3-3: if the structure trend and the inclination angle of the tunnel face of the advanced flat guide and the tunnel main hole differ by more than an acute angle, new dominant fracture structure surfaces are searched for the advanced flat guide and the tunnel face, and steps S2 and S3 are repeated until the condition is met.

[0011] Further, the specific method of the step S4 is: S4-1: judging the relative position of the measured low-resistance zone and the tunnel main hole according to S1-2; S4-2: calculating the fracture water gushing position of the tunnel main hole to be excavated according to the occurrence information of the through fracture structure surface, the width and distance of the advanced flat guide and the tunnel main hole, and the mileage of the low-resistance zone.

[0012] Further, in the step S4-2, if the center position of the low-resistance zone measured by S1 is outside the tunnel main hole, at this time, the distance y2 of the low-resistance zone to the side wall of the advanced flat guide is greater than the distance y1 of the side wall of the advanced flat guide to the side wall of the same side of the main hole, and the starting position x of the fracture water gushing of the tunnel main hole can be accurately inferred as x=x1+(y2-y1)tanα~x2+(y2-y1)tanα according to the trend of the through fracture structure surface J1" and the front side mileage x1 and the rear side mileage x2 of the low-resistance zone, wherein α is the included angle between the trend of the through fracture structure surface and the plane where the tunnel face is located.

[0013] Further, in the step S4-2, if the center position of the low-resistance zone measured by S1 is inside the contour line of the tunnel main hole, at this time, the distance y2 of the low-resistance zone to the side wall of the advanced flat guide is less than the distance y1 of the side wall of the advanced flat guide to the side wall of the same side of the main hole, but not less than the distance between the advanced flat guide and the main hole, and the starting position x of the fracture water gushing of the tunnel main hole can be accurately inferred as x=x1-(y1-y2)tanα~x2-(y1-y2)tanα according to the trend of the through fracture structure surface J1" and the front side mileage x1 and the rear side mileage x2 of the low-resistance zone, wherein α is the included angle between the trend of the through fracture structure surface and the plane where the tunnel face is located.

[0014] Further, in the step S4-2, if the center position of the low-resistance zone measured by S1 is inside the contour line of the tunnel main hole, at this time, the distance y2 of the low-resistance zone to the side wall of the advanced flat guide is less than the distance between the advanced flat guide and the main hole, and the starting position x of the fracture water gushing of the tunnel main hole can be accurately inferred as x=x1-(y1-y2)tanα~x2-(y1-y2)tanα according to the trend of the through fracture structure surface J1" and the front side mileage x1 and the rear side mileage x2 of the low-resistance zone, wherein α is the included angle between the trend of the through fracture structure surface and the plane where the tunnel face is located.

[0015] The beneficial effects of the present application are: 1) The application makes full use of the advantages of the high-risk tunnel advanced pilot, and predicts the water-occurring conditions of the bedrock fissure water in the long-distance predicted tunnel area to be excavated, which can provide sufficient time for the tunnel construction excavation to prepare water disaster prevention measures in advance; 2) The application predicts the fissure structure surface development in the unknown area between the tunnel advanced pilot and the tunnel main tunnel, and provides a deduction method of the through fissure structure surface, starting from the relationship between the tunnel advanced pilot and the tunnel main tunnel structure surface; 3) The application makes a spatial deduction of the advanced pilot surface to the tunnel main tunnel from the geological gestation law of the fissure structure surface, which is helpful to accurately predict the water-occurring conditions of the tunnel main tunnel area to be excavated, provides an advanced signal for the tunnel excavation water disaster prevention, and ensures the safety of the tunnel construction. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The application is a schematic diagram of the method principle; Figure 2 The application is a transient electromagnetic detection schematic diagram; Figure 3 The application is a schematic diagram of the occurrence information of the advanced pilot and the tunnel main tunnel advantage structure surface; Figure 4 The application is a schematic diagram of the occurrence of the through fissure structure surface; Figure 5 The application is a schematic diagram of the measured low-resistance area center position outside the tunnel main tunnel; Figure 6 The application is a schematic diagram of the measured low-resistance area center position inside the tunnel main tunnel; Figure 7 The application is a schematic diagram of the measured low-resistance area center position inside the tunnel main tunnel. DETAILED DESCRIPTION

[0017] The application will be described in detail below in combination with specific embodiments.

[0018] The application realizes efficient prediction of the fissure water in the tunnel advanced pilot surface to the main tunnel area to be excavated from the geological gestation law by means of the transient electromagnetic method.

[0019] The application method principle schematic diagram is shown in Figure 1 The application is a tunnel construction fissure water accurate detection method based on the advanced pilot, which includes the following steps: S1: determining the low-resistance area position of the tunnel main tunnel area to be excavated; S2: measuring a plurality of fissure structure surfaces in the exposed rock mass of the advanced pilot and the tunnel main tunnel heading face, and selecting the advantage fissure structure surface from the plurality of fissure structure surfaces; S3: Compare the occurrence information of the dominant fracture structure surface of the tunnel face and the tunnel face, and when the strike and dip angle of the dominant fracture structure surface of the tunnel face and the tunnel face are less than the acute angle, the average of the strike and dip angle is taken as the occurrence information of the through fracture structure surface; S4: According to the low-resistance zone position measured in S1, calculate the fracture water gushing position of the tunnel face to be excavated, the specific method is: S4-1: According to S1-2, determine the relative position of the measured low-resistance zone and the tunnel face; S4-2: According to the occurrence information of the through fracture structure surface in S3-2, the width and distance of the tunnel face and the tunnel face, and the mileage of the low-resistance zone, calculate the fracture water gushing position of the tunnel face to be excavated. Specific embodiments: Step S1: Use transient electromagnetic method to detect the tunnel face to be excavated in the side wall of the advanced flat guide, determine the position of the low-resistance zone, that is, the possible position of the disaster-causing water body; as shown in Figure 2 The specific method is: S1-1: Use transient electromagnetic method to detect the tunnel face to be excavated in the side wall of the tunnel advanced flat guide; S1-2: According to the transient electromagnetic detection data, analyze the spatial distribution and change of the resistivity, and determine the position of the low-resistance zone; the front side mileage of the low-resistance zone is recorded as x1, and the rear side mileage of the low-resistance zone is recorded as x2.

[0021] Step S2: Find out the more obvious structure surface in the exposed rock mass of the tunnel face and the tunnel advanced flat guide respectively, and select 2 groups of obvious and intuitive fracture structure surfaces as the dominant fracture structure surface; the specific method is: S2-1: Measure multiple fracture structure surfaces in the exposed bedrock of the tunnel advanced flat guide, and record the occurrence information, which includes the strike and dip angle of the fracture structure surface; S2-2: Measure multiple fracture structure surfaces in the exposed bedrock of the tunnel face, and record the occurrence information; S2-3: Compare the on-site tunnel face conditions in the multiple fracture structure surfaces in S2-1 and S2-2, and select 2 groups of fracture structure surfaces as the dominant fracture structure surface according to the length selection principle, the occurrence information of the first and second dominant fracture structure surfaces of the tunnel advanced flat guide is recorded as Ja and Jb respectively, and the occurrence information of the first and second dominant fracture structure surfaces of the tunnel face is recorded as Ja' and Jb' respectively, as shown in Figure 3 .

[0022] S3: Compare the occurrence information of the dominant fracture structure surface of the tunnel face and the tunnel face, and determine the occurrence information of the through fracture structure surface; the specific method is: Step S3-1: The occurrence information Ja', Jb' of the dominant fracture structure surface of the tunnel heading face and the two sets of occurrence information Ja, Jb of the dominant fracture structure surface of the advanced flat guide face are compared in turn, i.e. Ja' and Ja, Ja' and Jb, Jb' and Ja, Jb' and Jb; Step S3-2: If the occurrence (trend and dip angle) of the fracture structure surface of the advanced flat guide face and the tunnel heading face differs by less than an acute angle, the occurrence of the advanced flat guide face is named as J1, and the occurrence of the tunnel heading face is named as J1'. The trend of J1 and the trend of J1' are averaged to obtain the trend of the through fracture structure surface occurrence J1", and the dip angle of J1 and the dip angle of J1' are averaged to obtain the dip angle of the through fracture structure surface occurrence J1", as shown in Figure 4 . Step S3-3: If the occurrence trend and dip angle of the fracture structure surface of the advanced flat guide face and the tunnel heading face differ by more than an acute angle, new dominant fracture structure surfaces of the advanced flat guide face and the tunnel heading face are searched, and steps S2 and S3 are repeated until the condition is met.

[0023] S4: The position of the low-resistance zone measured by S1 can be outside the tunnel heading, inside the contour line of the tunnel heading, and inside the tunnel heading. According to the position of the low-resistance zone measured by S1, the position of the fracture water gushing of the tunnel heading to be excavated is calculated, and the specific method is as follows: S4-1: The relative position of the measured low-resistance zone and the tunnel heading is determined according to S1-2; S4-2: The position of the fracture water gushing of the tunnel heading to be excavated is calculated according to the occurrence information of the through fracture structure surface, the width and distance of the advanced flat guide face and the tunnel heading, and the mileage of the low-resistance zone.

[0024] 1) In step S4-2, if the center position of the low-resistance zone measured by S1 is outside the tunnel heading, as shown in Figure 5 , at this time, the distance y2 between the low-resistance zone and the side wall of the advanced flat guide face is greater than the distance y1 between the side wall of the advanced flat guide face and the side wall on the same side of the tunnel heading. According to the trend of the through fracture structure surface occurrence J1", the front side mileage x1 and the rear side mileage x2 of the low-resistance zone can be accurately predicted to obtain the starting position of the fracture water gushing of the tunnel heading as x = x1 + (y2 - y1) tan α ~ x2 + (y2 - y1) tan α, where α is the angle between the trend of the through fracture structure surface and the plane of the tunnel heading face.

[0025] 2) In step S4-2, if the center position of the low-resistance zone measured by S1 is inside the contour line of the tunnel heading, as shown in Figure 6As shown in the figure, at this time, the distance between the low-resistance area and the leading flat pilot side wall is y2, which is less than the distance y1 between the flat pilot side wall and the side wall of the main tunnel on the same side of the flat pilot, but not less than the distance between the flat pilot and the main tunnel. Through the attitude of the through-fracture structure surface J1", according to its strike and the mileage x1 in front of the low-resistance area and the mileage x2 in the back of the low-resistance area, the starting position of the fissure water inrush in the main tunnel of the tunnel can be accurately inferred to be x=x1-(y1-y2)tanα~x2-(y1-y2)tanα, where α is the angle between the strike of the through-fracture structure surface and the plane where the tunnel main tunnel face is located.

[0026] 3) In step S4-2, if the center of the low resistance area measured by S1 is inside the tunnel, Figure 7 As shown in the figure, at this time, the distance between the low-resistance area and the side wall of the leading pilot is y2, which is less than the distance between the pilot and the main tunnel. Through the attitude of the through-fracture structure surface J1", according to its strike and the mileage x1 in front of the low-resistance area and the mileage x2 in the back of the low-resistance area, the starting position of the fissure water inrush in the main tunnel of the tunnel can be accurately inferred to be x=x1-(y1-y2)tanα~x2-(y1-y2)tanα, where α is the angle between the strike of the through-fracture structure surface and the plane where the tunnel main tunnel face is located.

[0027] The content of the present invention is not limited to the embodiments listed. Any equivalent transformation of the technical solution of the present invention made by ordinary technicians in this field after reading the description of the present invention is covered by the claims of the present invention.

Claims

1. A method for accurate detection of fissure water in tunnel construction based on advanced flat guide, characterized by: The steps include: S1: Determine the location of the low-resistance area in the high-risk tunnel to be excavated; S2: measuring multiple groups of fracture structural surfaces in the exposed rock mass of the advanced pilot and the tunnel face, and selecting the dominant fracture structural surface from the multiple groups of fracture structural surfaces; S3: Compare the dominant fracture structure surface information of the advanced pilot and the tunnel face. When the difference between the strike and dip of the dominant fracture structure surface of the advanced pilot and the tunnel face is less than the acute angle, take the average of the strike and dip of this group and use it as the occurrence information of the through-fracture structure surface. S4: Based on the low-resistance area position measured by S1, calculate the location of fissure water inrush in the tunnel main tunnel to be excavated area.

2. The method for accurate detection of fissure water in tunnel construction based on advanced flat guide according to claim 1 is characterized by: The specific method of step S1 is: S1-1: Transient electromagnetic method is used to detect the unexcavated section of the tunnel main tunnel on the side wall of the tunnel advance guide; S1-2: Analyze the spatial distribution and variation of resistivity based on transient electromagnetic detection data to determine the location of low-resistance areas.

3. The method for accurate detection of fissure water in tunnel construction based on advanced flat guide according to claim 2 is characterized by: The specific method of step S2 is: S2-1: Measure multiple groups of fracture structures in the exposed bedrock at the tunnel face of the advanced flat guide and record the occurrence information; S2-2: Measure multiple groups of fracture structures in the exposed bedrock at the tunnel face and record the occurrence information; S2-3: The on-site face conditions were compared among the multiple groups of fracture structural surfaces in S2-1 and S2-2. Based on the principle of selecting the longest fracture length, two groups of fracture structural surfaces were selected as the dominant fracture structural surfaces. The strike information of the first and second groups of dominant fracture structural surfaces in the advanced pilot were recorded as Ja and Jb, respectively. The strike information of the first and second groups of dominant fracture structural surfaces in the main tunnel were recorded as Ja' and Jb', respectively.

4. The method for accurate detection of fissure water in tunnel construction based on advanced flat guide according to claim 3 is characterized by: The occurrence information includes the strike and dip of the fracture structural surface.

5. The method for accurate detection of fissure water in tunnel construction based on advanced flat guide according to claim 4 is characterized by: The specific method of step S3 is: Step S3-1: Alternately compare the dominant fracture structure surface Ja' and Jb' of the tunnel main face with the dominant fracture structure surface Ja and Jb of the advanced pilot face, i.e., Ja' and Ja, Ja' and Jb, Jb' and Ja, and Jb' and Jb; Step S3-2: If the differences in the strike and dip of the fracture structure surface at the leading guide and the tunnel face are both less than an acute angle, the strike corresponding to the leading guide is named J1, and the strike corresponding to the tunnel face is named J1'. The strikes of J1 and J1' are averaged as the strike of the fracture structure surface J1", and the dips of J1 and J1' are averaged as the dip of the fracture structure surface J1". Step S3-3: If the difference between the strike direction and inclination angle of the leading flat guide and the tunnel face is greater than the acute angle, a new dominant fracture structure surface is searched for the leading flat guide and the tunnel face, and steps S2 and S3 are repeated until the conditions are met.

6. The method for accurate detection of fissure water in tunnel construction based on advanced flat guide according to claim 5, characterized in that: The specific method of step S4 is: S4-1: Determine the relative position of the low-resistance area and the tunnel main hole measured according to S1-2; S4-2: Based on the attitude information of the fracture structure surface penetrating S3-2, the width and distance between the advance pilot and the tunnel main tunnel, and the mileage of the low-resistance area, the location of the fracture water gushing in the area to be excavated in the tunnel main tunnel is calculated.

7. The method for accurate detection of fissure water in tunnel construction based on advanced flat guide according to claim 6, characterized in that: In step S4-2, if the center position of the low-resistance zone measured by S1 is outside the main tunnel, at this time, the distance y2 between the low-resistance zone and the leading guide side wall is greater than the distance y1 between the guide side wall and the side wall on the same side of the main tunnel. Through the attitude J1" of the through-fracture structure surface, according to its strike and the mileage x1 in front of the low-resistance zone and the mileage x2 behind the low-resistance zone, the starting position of the fissure water inrush in the main tunnel of the tunnel can be accurately inferred to be x=x1+(y2-y1)tanα~x2+(y2-y1)tanα, where α is the angle between the strike of the through-fracture structure surface and the plane where the tunnel main tunnel face is located.

8. The method for accurate detection of fissure water in tunnel construction based on advanced flat guide according to claim 7, characterized in that: In step S4-2, if the center position of the low-resistance area measured by S1 is within the outline of the tunnel main tunnel, at this time, the distance between the low-resistance area and the leading flat guide side wall is y2, which is less than the distance y1 between the flat guide side wall and the side wall on the same side of the main tunnel, but not less than the distance between the flat guide and the main tunnel. Through the attitude J1" of the through-fracture structure surface, according to its strike and the mileage x1 in front of the low-resistance area and the mileage x2 in the rear of the low-resistance area, the starting position of the fissure water inrush in the tunnel main tunnel can be accurately inferred to be x=x1-(y1-y2)tanα~x2-(y1-y2)tanα, where α is the angle between the strike of the through-fracture structure surface and the plane where the tunnel main tunnel face is located.

9. The method for accurate detection of fissure water in tunnel construction based on advanced flat guide according to claim 8, characterized in that: In step S4-2, if the center position of the low-resistance area measured by S1 is within the outline of the tunnel main tunnel, at this time, the distance between the low-resistance area and the side wall of the leading flat guide is y2, which is less than the distance between the flat guide and the main tunnel. Through the attitude J1" of the through-fracture structure surface, according to its strike and the mileage x1 in front of the low-resistance area and the mileage x2 in the rear of the low-resistance area, the starting position of the fissure water inrush in the tunnel main tunnel can be accurately inferred to be x=x1-(y1-y2)tanα~x2-(y1-y2)tanα, where α is the angle between the strike of the through-fracture structure surface and the plane where the tunnel main tunnel face is located.

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