Multi-layer weak interlayer gravity dam foundation geological exploration work well structure and construction method

Abstract

The application provides a multi-layer weak interlayer gravity dam foundation geological exploration work well structure and construction method, which comprises a plurality of cast-in-place piles vertically inserted into the stratum, and all the cast-in-place piles are arranged around a cylindrical well wall structure with an exploration gap; the inner wall of the well wall structure is equidistantly arranged with waist beams along the axis, the waist beams are attached to the cast-in-place piles, an observation window is arranged at the exploration gap of the well wall structure, the observation window is located between adjacent waist beams, and a transparent water baffle and a rectangular metal support frame are arranged in the observation window. The application has the effects of improving the accuracy, convenience and safety of detection sampling.

Description

Technical Field

[0001] This invention relates to the field of gravity dam foundation reinforcement technology for hydropower projects, and particularly to the structure and construction method of geological exploration wells for multi-layered weak interlayer gravity dam foundations. Background Technology

[0002] Gravity dams are among the most commonly used water-retaining structures in hydropower projects, primarily relying on the anti-sliding force generated by the dam's own weight to meet stability requirements. When a gravity dam foundation contains multiple weak interlayers, it negatively impacts its deep anti-sliding stability, affecting the dam's operational safety. To reasonably evaluate its anti-sliding stability and formulate economical and effective reinforcement and seepage prevention measures, it is necessary to investigate its detailed geological conditions and take samples for physical and mechanical tests to obtain its shear mechanical parameters and permeability characteristics. Traditional geological drilling methods struggle to accurately obtain geological information such as the specific depth, thickness, and occurrence of each weak interlayer. Moreover, core drilling causes significant disturbance, making it difficult to obtain complete samples of the weak interlayers, thus affecting the accuracy of mechanical tests. Therefore, an exploration well structure is needed that can accurately detect the geological information of each weak interlayer and perform in-situ sampling of the weak interlayers. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a structure and construction method for a geological exploration well for a multi-layered weak interlayer gravity dam foundation, which solves the problems of poor accuracy in core sampling and the low precision of test results in existing technologies.

[0004] According to an embodiment of the present invention, a geological exploration well structure for a multi-layered weak interlayer gravity dam foundation includes multiple vertically inserted cast-in-place piles, all of which surround a cylindrical well wall structure with an exploration opening. The inner wall of the well wall structure is equidistantly arranged with waist beams along the axis, the waist beams being fitted to the cast-in-place piles. An observation window is provided at the exploration opening of the well wall structure, located between adjacent waist beams. The observation window contains a transparent water-blocking plate and a rectangular metal support frame.

[0005] Preferably, the outer walls of adjacent cast-in-place piles fit together, and a notch is provided on the outer wall of the waist beam around its axis.

[0006] And it fits against the outer wall of all the cast-in-place piles through the notch.

[0007] Preferably, the cast-in-place pile is formed by drilling holes in the ground and then grouting, and the waist beam is formed by excavating to a fixed depth along the cast-in-place pile and then grouting.

[0008] Preferably, the waist beam fills the exploration gap area in the plane in which it is located.

[0009] Preferably, the outer wall of the observation window is provided with an arc-shaped notch, and the arc-shaped notch is fitted to the outer wall of the cast-in-place pile. A transverse support structure is provided inside the observation window, and a stop block is fixedly provided on the outer side of the observation window. The water baffle is located between the transverse support structure and the stop block.

[0010] Preferably, the observation window includes two longitudinal beams and two transverse beams, with the two transverse beams fixed between the top and bottom of the two longitudinal beams, respectively.

[0011] Preferably, the lateral support structure includes a hydraulic support component, which includes a hydraulic sleeve and a telescopic rod axially slidably mounted on one end of the hydraulic sleeve. An oil guide pipe is connected to the side wall of the hydraulic sleeve away from the telescopic rod. The movable ends of the hydraulic sleeve and the telescopic rod are respectively connected to the opposite inner side walls of the observation window.

[0012] Preferably, the movable ends of the hydraulic sleeve and the telescopic rod are both vertically fixedly connected to push plates, which contact the opposite inner sidewall of the observation window.

[0013] Preferably, the water baffle is made of transparent fiberglass.

[0014] The construction method for the geological exploration well structure of a multi-layered weak interlayer gravity dam foundation includes the following steps:

[0015] S1. Drill holes for grouting around the location of the exploration well, then put the steel cage into the grouting holes, and then pour concrete into all the grouting holes to form grouting piles. All the grouting piles form a cylindrical well wall structure with exploration gaps.

[0016] S2. Pour an arc-shaped waist beam at the top of the cylindrical well wall structure, and keep the outer wall of the waist beam connected to all the cast-in-place piles as a whole.

[0017] S3. After the top waist beam is formed, continue to excavate downwards along the inner wall of the cylindrical well wall structure, and pour a waist beam for each section excavated.

[0018] S4. Install an observation window in the exploration gap between the two waist beams, and sample the soil outside the cylindrical well wall structure before installing the water baffle. Sampling the soil is carried out in sequence until the excavation reaches the specified depth, thus completing the construction process of the working well. The staff can see complete stratum information from top to bottom through the observation window of the working well.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The working well for this geological exploration includes cast-in-place piles. All cast-in-place piles are inserted into the strata to form a well wall structure with detection gaps. The well wall structure is equipped with multiple spaced-apart annular waist beams, and observation windows are provided between adjacent annular waist beams to facilitate direct survey of the geological conditions inside the well wall structure.

[0021] 2. The well wall structure supports the soil, and the ring-shaped waist beam is used to support the well wall, improve the structural strength of the working well, and ensure the safety of exploration and sampling.

[0022] 3. The structure of this working well can be excavated step by step from top to bottom, making construction convenient.

[0023] 4. During the excavation process, soil samples can be taken in situ for physical and mechanical tests, thereby accurately obtaining the mineral composition, shear mechanical parameters and permeability parameters of each weak interlayer.

[0024] 5. After excavation is completed, the geological information such as the depth, thickness, and attitude of the strata can be seen from top to bottom through the observation window. At the same time, after the exploration and sampling work is completed, concrete can be backfilled in the working well to reinforce the gravity dam foundation. Attached Figure Description

[0025] Figure 1 is a top view of the present invention;

[0026] Figure 2 yes Figure 1 Enlarged view of point A in the middle;

[0027] Figure 3 yes Figure 1 Cross-sectional view at point BB;

[0028] Figure 4 yes Figure 3 Enlarged view at point C;

[0029] Figure 5 yes Figure 3 Cross-sectional view at point DD.

[0030] In the diagram: 1. Cast-in-place pile; 11. Exploration gap; 2. Waist beam; 3. Observation window; 31. Longitudinal beam; 32. Cross beam; 33. Stop block; 34. Water baffle; 4. Hydraulic support component; 41. Hydraulic sleeve; 42. Telescopic rod; 43. Push plate; 44. Oil guide pipe. Detailed Implementation

[0031] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] As shown in Figures 1-5, this invention proposes a geological exploration well structure for a multi-layered weak interlayer gravity dam foundation, comprising multiple vertically inserted cast-in-place piles 1, all of which surround a cylindrical well wall structure with an exploration gap 11. The inner wall of the well wall structure is equidistantly arranged with waist beams 2 along the axis, the waist beams 2 fitting snugly against the cast-in-place piles 1. Observation windows 3 are provided at the exploration gap 11 of the well wall structure, located between adjacent waist beams 2. Transparent baffles 34 and rectangular metal support frames are installed inside the observation windows 3.

[0033] All cast-in-place piles 1 and waist beams 2 are reinforced concrete structures. The cast-in-place piles 1 are obtained by drilling grouting holes and then injecting concrete. The soil inside the cylindrical well wall structure is gradually excavated. The waist beams 2 are set at equal intervals from top to bottom along the axis of the cylindrical well wall structure, and the spacing between adjacent waist beams 2 is equal. The soil of the cylindrical well wall structure is excavated in a step-by-step manner, that is, after each section of soil is excavated, a ring of waist beams 2 is poured, which can ensure construction safety.

[0034] As shown in Figures 1 and 5, the outer walls of adjacent cast-in-place piles 1 are fitted together, and the outer wall of the waist beam 2 has a notch around its axis, which fits into the outer walls of all the cast-in-place piles 1.

[0035] As a preferred embodiment of the present invention, the cast-in-place pile 1 is formed by drilling holes in the ground and then grouting, and the waist beam 2 is formed by excavating along the cast-in-place pile 1 to a fixed depth and then grouting.

[0036] As shown in Figures 1-4, to ensure the stability of the exploration gap 11, the waist beam 2 fills the area of ​​the exploration gap 11 in its plane.

[0037] As shown in Figure 2, to ensure the overall sealing of the cylindrical well wall structure after the observation window 3 is installed, the outer wall of the observation window 3 is provided with an arc-shaped notch, which fits against the outer wall of the cast-in-place pile 1. A transverse support structure is provided inside the observation window 3, and a stop block 33 is fixedly installed on the outer side of the observation window 3. The water-blocking plate 34 is located between the transverse support structure and the stop block 33. The stop block 33 is used to limit the water-blocking plate 34, which is used to prevent formation seepage water from flowing into the working well.

[0038] As shown in Figure 2, the observation window 3 includes two longitudinal beams 31 and two transverse beams 32, with the two transverse beams 32 fixed between the top and bottom of the two longitudinal beams 31, respectively.

[0039] Viewing window 3 provides a complete view of the geological strata from top to bottom. It also allows for convenient sampling of soil at all elevations, improving the accuracy of gravity dam foundation exploration.

[0040] As shown in Figure 2, the transverse support structure includes a hydraulic support 4, which comprises a hydraulic sleeve 41 and a telescopic rod 42 axially slidably mounted on one end of the hydraulic sleeve 41. An oil guide pipe 44 is connected to the side wall of the hydraulic sleeve 41 away from the telescopic rod 42. The movable ends of the hydraulic sleeve 41 and the telescopic rod 42 are respectively connected to the opposite inner side walls of the observation window 3. The hydraulic support 4 is used to strengthen the observation window 3 and prevent it from deforming under stress. A hydraulic valve is provided on the oil guide pipe 44, through which hydraulic oil is injected into the hydraulic sleeve 41, causing the telescopic rod 42 to extend from the hydraulic sleeve 41 and support the two longitudinal beams 31. After the oil is injected into the oil guide pipe 44, closing the hydraulic valve maintains the pressure of the hydraulic oil in the hydraulic sleeve 41.

[0041] As shown in Figures 2 and 4, to ensure that the hydraulic sleeve 41 and the telescopic rod 42 are fully fitted against the relative inner walls of the observation window 3, the movable ends of both the hydraulic sleeve 41 and the telescopic rod 42 are vertically fixedly connected to push plates 43, which then contact the relative inner walls of the observation window 3.

[0042] In a preferred embodiment of the present invention, to facilitate workers' observation of geological information through the water-blocking plate 34, and the water-blocking plate 34 has a certain strength, the water-blocking plate 34 is made of transparent fiberglass.

[0043] The construction method of the geological exploration well structure of the multi-layer soft interlayer gravity dam foundation includes the following steps: S1, drilling injection holes around the location of the exploration well, then placing the steel cage into the injection holes, and then pouring concrete into all injection holes to form injection piles 1. All injection piles 1 form a cylindrical well wall structure with exploration gaps 11.

[0044] S2. Pour an arc-shaped waist beam 2 into the top of the cylindrical well wall structure, and keep the outer wall of the waist beam 2 connected to all the cast-in-place piles 1 as a whole.

[0045] S3. After the top waist beam 2 is formed, continue to excavate downwards along the inner wall of the cylindrical well wall structure, and pour a waist beam 2 for each section excavated.

[0046] S4. Install observation window 3 in the exploration gap 11 between the two waist beams 2, and sample the soil outside the cylindrical well wall structure before installing the water baffle 34. Sample the soil in sequence until the excavation reaches the specified depth, thus completing the construction process of the working well.

Claims

1. A geological exploration well structure for a multi-layered, weak interlayered gravity dam foundation, characterized in that: It includes multiple vertically inserted cast-in-place piles (1), and all the cast-in-place piles (1) are arranged in a cylindrical well wall structure with an exploration gap (11); The inner wall of the well wall structure is equidistantly arranged with waist beams (2) along the axis. The waist beams (2) are attached to the cast-in-place piles (1). An observation window (3) is set at the exploration gap (11) of the well wall structure. The observation window (3) is located between adjacent waist beams (2). A transparent water baffle (34) and a rectangular metal support frame are set inside the observation window (3). The outer walls of adjacent cast-in-place piles (1) are in contact with each other, and the outer wall of the waist beam (2) is provided with a notch around the axis, and is in contact with the outer walls of all the cast-in-place piles (1) through the notch; The outer wall of the observation window (3) is provided with an arc-shaped notch, and it fits against the outer wall of the cast-in-place pile (1) through the arc-shaped notch. A transverse support structure is provided inside the observation window (3). A block (33) is fixedly provided on the outer side of the observation window (3). The water baffle (34) is located between the transverse support structure and the block (33). The transverse support structure includes a hydraulic support (4), which includes a hydraulic sleeve (41) and a telescopic rod (42) axially slidably mounted on one end of the hydraulic sleeve (41). An oil guide pipe (44) is connected to the side wall of the hydraulic sleeve (41) away from the telescopic rod (42). The movable ends of the hydraulic sleeve (41) and the telescopic rod (42) are respectively connected to the opposite inner side walls of the observation window (3).

2. The geological exploration well structure for a multi-layered weak interlayer gravity dam foundation as described in claim 1, characterized in that: The cast-in-place pile (1) is formed by drilling holes in the ground and then grouting, and the waist beam (2) is formed by excavating to a fixed depth along the cast-in-place pile (1) and then grouting.

3. The geological exploration well structure for a multi-layered weak interlayer gravity dam foundation as described in claim 2, characterized in that: The waist beam (2) fills the area of ​​the exploration gap (11) in the plane in which it is located.

4. The geological exploration well structure for a multi-layered weak interlayer gravity dam foundation as described in claim 1, characterized in that: The observation window (3) includes two longitudinal beams (31) and two transverse beams (32), with the two transverse beams (32) fixed between the top and bottom of the two longitudinal beams (31), respectively.

5. The geological exploration well structure for a multi-layered weak interlayer gravity dam foundation as described in claim 1, characterized in that: The movable ends of the hydraulic sleeve (41) and the telescopic rod (42) are both vertically fixedly connected to push plates (43) and contact the relative inner sidewall of the observation window (3) through the push plates (43).

6. The geological exploration well structure for a multi-layered weak interlayer gravity dam foundation as described in claim 1, characterized in that: The water baffle (34) is made of transparent fiberglass.

7. The construction method of the geological exploration well structure for a multi-layered weak interlayer gravity dam foundation as described in claim 1, characterized in that, Includes the following steps: S1. Drill holes for grouting around the location of the exploration well, then put the steel cage into the grouting hole, and then pour concrete into all the grouting holes to form grouting piles (1). All the grouting piles (1) form a cylindrical well wall structure with exploration gaps (11). S2. A circular arc-shaped waist beam (2) is poured into the top of the cylindrical well wall structure, and the outer wall of the waist beam (2) is connected to all the cast-in-place piles (1) as a whole. S3. After the top waist beam (2) is formed, continue to excavate downward along the inner wall of the cylindrical well wall structure, and pour a waist beam (2) for each section excavated. S4. Install an observation window (3) in the exploration gap (11) between the two waist beams (2), and sample the soil outside the cylindrical well wall structure before installing the water baffle (34). Sample the soil in sequence until the excavation reaches the specified depth, thus completing the construction process of the working well. The staff can see the complete stratum information from top to bottom through the observation window (3) of the working well.

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