Well wall structure and construction method based on stratum water yield property segmented optimization

Abstract

The invention discloses a well wall structure and a construction method based on stratum water yield segmented optimization, and relates to the technical field of mine construction engineering. The well wall structure comprises an inner-layer well wall body corresponding to a strong aquifer, an inner-layer well wall body corresponding to a weak aquifer and a waterproof wall ring; the inner-layer well wall main body corresponding to the strong water-bearing layer, the inner-layer well wall main body corresponding to the weak water-bearing layer and the waterproof wall ring are integrally poured and formed, and the inner-layer well wall main body corresponding to the strong water-bearing layer and the inner-layer well wall main body corresponding to the weak water-bearing layer are separated through the waterproof wall ring; an outer-layer well wall is poured between the upper waterproof wall ring and the lower waterproof wall ring. According to the well wall structure based on stratum water-rich property segmented optimization and the construction method, the well wall structure construction process is simple, the overall water sealing performance is good, the deep and large vertical shaft well wall structure can be specifically designed and refined in a segmented mode in the vertical direction, the well wall structure in a deep water-rich rock stratum is optimized, and the well wall manufacturing cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of mine construction engineering, and in particular to a shaft wall structure and a construction method based on segmented optimization of stratum water richness. Background Art

[0002] For deep water-rich rock formations, high-efficiency water sealing is still the key and difficult problem in vertical shaft construction. At present, although double-layer well walls or double-layer composite well walls can achieve superior water sealing performance in deep water-rich rock formations, the two well wall structures and their construction processes completely follow the well-drilling technology and construction experience in deep alluvial layers in the central and eastern regions, and have not been targeted for research and improvement based on the hydrogeological conditions of water-rich rock formations. As a result, the current design theories, methods, specifications and standards for frozen well walls and even non-frozen wells are difficult to scientifically guide the construction of deep and large vertical shafts in deep water-rich rock formations; the well wall structure and parameters designed according to the current specifications are not compatible with the characteristics of deep water-rich rock formations, resulting in thick well walls, easy cracking, and poor waterproof performance. At the same time, it causes problems such as large well-drilling engineering volume and difficulty, large investment and long construction period.

[0003] The double-layer well wall or double-layer composite well wall structure in deep topsoil has an outer well wall mainly used to resist freezing pressure and construction loads, and the inner well wall is designed to resist full water pressure. The inner and outer well walls jointly bear permanent ground pressure. A relatively complete design theory has been formed in a large number of engineering practices. However, for double-layer well walls or double-layer composite well walls in water-rich rock formations, due to the high strength of frozen rocks, the frozen wall is basically in an elastic state during excavation, so the outer well wall can be taken according to experience. According to current specifications, the inner well wall should be calculated according to full water pressure. As the thickness of the water-rich rock formations that deep vertical shafts in my country have to pass through becomes larger and larger, a considerable number of wells will pass through rock formations as deep as 1000 to 1500 meters or more. Under this condition, the design of the frozen shaft wall structure in the bedrock section still follows the design method of the frozen shaft wall in the surface soil layer. It is designed according to the current "Design Code for Coal Mine Vertical Shaft and Chamber". When the double-layer composite shaft wall structure is used, even if C80 concrete support is used for some large-diameter deep shafts, the total thickness of the shaft wall will still exceed 3.0 m (of which the thickness of the inner shaft wall exceeds 2.5 m). The utilization rate of the shaft excavation section (the ratio of the net cross-sectional area of ​​the shaft to the excavation cross-sectional area) is less than 30%. Therefore, the construction cost of the composite shaft wall in the bedrock section must be very high, which also greatly increases the construction cost of the shaft freezing and other projects, and prolongs the construction period of the shaft. With the increase of the shaft construction depth, the double-layer shaft wall or double-layer composite shaft wall structure is becoming more and more unreasonable.

[0004] How to develop a shaft wall structure and construction method based on segmented optimization of formation water-richness, reduce shaft wall thickness, improve shaft excavation section utilization rate, and thereby reduce project costs has become a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0005] The purpose of the present invention is to provide a well wall structure and construction method based on segmented optimization of formation water-richness, so as to solve the problems listed in the background technology.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a well wall structure and construction method based on segmented optimization of formation water-richness, comprising an inner well wall body corresponding to a strong aquifer, an inner well wall body corresponding to a weak aquifer, and a water-blocking wall ring, wherein the inner well wall body corresponding to the strong aquifer, the inner well wall body corresponding to the weak aquifer, and the water-blocking wall ring are integrally cast and formed, and the inner well wall body corresponding to the strong aquifer and the inner well wall body corresponding to the weak aquifer are separated by the water-blocking wall ring; An outer well wall is cast between the upper and lower water-blocking wall circles.

[0007] Preferably, a temporary support is installed on the outer side wall of the waterproof wall circle, and the temporary support is connected to the waterproof layer.

[0008] Preferably, the temporary support adopts hanging nets and / or anchor rods.

[0009] Preferably, the main body of the inner well wall corresponding to the strong aquifer corresponds to the strong aquifer, and the main body of the inner well wall corresponding to the weak aquifer corresponds to the weak aquifer.

[0010] Preferably, the wall thickness of the inner well wall body corresponding to the strong aquifer is greater than the wall thickness of the inner well wall body corresponding to the weak aquifer.

[0011] Preferably, the outer well wall is cast on the outer side walls of the inner well wall body corresponding to the strong aquifer and the inner well wall body corresponding to the weak aquifer, and an interlayer is installed between the outer side walls of the inner well wall body corresponding to the strong aquifer and the inner well wall body corresponding to the weak aquifer and the side walls of the outer well wall.

[0012] Preferably, the interlayer is made of plastic board, foam board or the interface between new and old concrete.

[0013] A method for constructing a wellbore structure based on segmented optimization of formation water-richness comprises the following steps: S1. Well inspection hole detection determines the well wall structure. The position and shape of the water-blocking wall ring are determined according to the well wall structure requirements and the hydrological and geological conditions of the wellbore passing through the stratum. The shape of the water-blocking wall ring is achieved by adjusting the template and its blade foot used in the casting process of the outer well wall; S2, start the construction of the outer well wall, dig and cast the outer well wall in sections from top to bottom; S3, reserved pouring area construction, when the outer well wall is constructed to the position of the water-blocking wall ring determined in S1, a temporary support method is used to reserve the pouring area of ​​the water-blocking wall ring; S4, the outer well wall is constructed to a predetermined depth, and the operations of steps S2 and S3 are repeated until the predetermined depth is reached; S5. Laying of interlayer: a interlayer is set between the inner well wall body and the outer well wall as needed. The interlayer is a plastic board or the interface between new and old concrete; S6. Construction of the inner well wall body and watertight wall ring: The inner well wall body and watertight wall ring are continuously cast from bottom to top to form an integrated structure, and 8 to 12 grouting pipes are pre-buried in the circumference at intervals of no more than 20m along the vertical direction for grouting in the interlayer later; the inner well wall body is designed in sections according to the properties of the aquifer and geological conditions, and is divided into the inner well wall body corresponding to the weak aquifer and the inner well wall body corresponding to the strong aquifer. Its thickness, material and structure can be constructed differently according to the hydrological and geological conditions; S7. Grouting construction in the interlayer. After the construction of the main body of the inner well wall and the waterproof wall ring is completed, use pre-buried or drilled grouting pipes as needed to inject micro-expansion slurry into the interlayer between the inner and outer well walls. The final grouting pressure of each hole should reach the design pressure. According to construction needs, a waterproof wall ring can also be added in the aquifer to reduce the vertical flow range of the slurry in the interlayer and improve the grouting quality.

[0014] Compared with the prior art, the beneficial technical effects of the present invention are: The present invention discloses a well wall structure and construction method based on the segmented optimization of the water-rich formation. When constructing the outer well wall, a casting area for the water-blocking wall ring is reserved in a temporary support manner. When the inner well wall is to be built, the inner well wall body and the water-blocking wall ring are cast in an integral form to form a new well wall structure that can be segmented and optimized based on the water-rich formation. This well wall structure uses the water-blocking wall ring to cut off the connection between the upper and lower aquifers, and structurally segments and classifies the well wall and the strata through which it passes. Then, according to the hydrological and geological conditions of the strata through which it passes, the well wall structure of each section is reasonably optimized, and a drainage or resistance strategy is selectively implemented for the water pressure between the inner and outer well walls of each section, providing technical support for thinning the thickness of the inner well wall. This well wall structure has a simple construction process and good overall water-sealing performance, and can realize the targeted segmented design and improvement of the well wall structure of deep and large vertical shafts in the vertical direction, optimize the well wall structure in deep water-rich rock formations, and reduce the cost of the wellbore. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings.

[0016] Figure 1 A schematic cross-sectional view of a well wall structure based on segmented optimization of formation water-richness according to the present invention; Figure 2 This is a flow chart of a construction method of a well wall structure based on segmented optimization of formation water-richness according to the present invention; Figure 3 The radial stress cloud diagram of the inner well wall during the use stage of the present invention; Figure 4 The hoop stress cloud diagram of the inner well wall during the use stage of the present invention; Figure 5 A comparison diagram of the finite element and analytical solutions of surrounding rock stress during the tunneling stage of the present invention; Figure 6 It is a comparison diagram of the finite element and analytical solutions of surrounding rock displacement in the excavation stage of the present invention; Figure 7 This is a finite element and analytical comparison diagram of frozen wall stress in the excavation stage of the present invention; Figure 8 It is a finite element and analytical comparison diagram of the frozen wall displacement in the excavation stage of the present invention; Fig. 9 This is a finite element and analytical comparison diagram of the stress of the outer well wall during the outer well wall masonry stage of the present invention; Fig.10 This is a finite element and analytical comparison diagram of the displacement of the outer well wall during the outer well wall construction stage of the present invention; Fig.11 This is a finite element and analytical comparison diagram of the outer well wall stress during the use stage of the present invention; Fig.12 The finite element and analytical comparison diagram of the outer wellbore displacement during the use stage of the present invention; Fig.13 The finite element and analytical comparison diagram of the inner well wall stress during the use stage of the present invention; Fig.14 This is a comparison diagram of the finite element and analytical methods for the inner wellbore displacement during the use phase of the present invention.

[0017] Explanation of the accompanying reference numerals: 11. Inner well wall main body corresponding to the weak aquifer; 12. Inner well wall main body corresponding to the strong aquifer; 13. Water-proof wall ring; 14. Temporary support; 2. Outer well wall; 3. Interlayer; 4. Weak aquifer; 5. Strong aquifer; 6. Water-proof layer. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] like Figure 1As shown, a wellbore structure based on segmented optimization of formation water-richness comprises an inner wellbore body 11 corresponding to a weak aquifer, an inner wellbore body 12 corresponding to a strong aquifer and a water-blocking wall ring 13, wherein the inner wellbore body 11 corresponding to the weak aquifer, the inner wellbore body 12 corresponding to the strong aquifer and the water-blocking wall ring 13 are integrally cast and formed, and the inner wellbore body 11 corresponding to the weak aquifer and the inner wellbore body 12 corresponding to the strong aquifer are separated by the water-blocking wall ring 13; the inner wellbore body 11 corresponding to the weak aquifer corresponds to the weak aquifer 4, and the inner wellbore body 12 corresponding to the strong aquifer corresponds to the strong aquifer 5; An outer well wall 2 is cast between the upper and lower waterproof wall circles 13, and a temporary support 14 is installed on the outer side wall of the waterproof wall circle 13, and the temporary support 14 is connected to the waterproof layer 6; the waterproof wall circle 13 in direct contact with the waterproof layer 6 cuts off the vertical connection between different aquifers, and also blocks the strata with different hydrogeological conditions in a targeted manner, and structurally segments and classifies the well wall and the strata passed through; based on this well wall structure, in the well wall design process, the structure and materials of each section of the well wall can be reasonably optimized according to the hydrological and geological conditions of the strata passed through, and the water pressure between the inner and outer well walls of each section can be selectively released or resisted, providing technical support for thinning the thickness of the inner well wall.

[0020] Specifically, the temporary support 14 uses hanging nets and / or anchor rods.

[0021] Specifically, the wall thickness of the inner well wall body 11 corresponding to the weak aquifer is smaller than the wall thickness of the inner well wall body 12 corresponding to the strong aquifer.

[0022] Specifically, the outer wall of the inner well wall body 11 corresponding to the weak aquifer and the outer wall of the inner well wall body 12 corresponding to the strong aquifer are cast with the outer well wall 2, and an interlayer 3 is installed between the outer wall of the inner well wall body 11 corresponding to the weak aquifer and the outer wall of the inner well wall body 12 corresponding to the strong aquifer and the side wall of the outer well wall 2.

[0023] Specifically, the interlayer 3 is made of plastic board, foam board or the interface between new and old concrete.

[0024] like Figure 2 As shown, a wellbore structure construction method based on segmented optimization of formation water-richness includes the following steps: S1. Well inspection hole detection determines the well wall structure. The position and shape of the water-blocking wall ring are determined according to the well wall structure requirements and the hydrological and geological conditions of the wellbore passing through the stratum. The shape of the water-blocking wall ring is achieved by adjusting the template and its blade foot used in the casting process of the outer well wall; S2, start the construction of the outer well wall, dig and cast the outer well wall in sections from top to bottom; S3, reserved pouring area construction, when the outer well wall is constructed to the position of the water-blocking wall ring determined in S1, a temporary support method is used to reserve the pouring area of ​​the water-blocking wall ring; S4, the outer well wall is constructed to a predetermined depth, and the operations of steps S2 and S3 are repeated until the predetermined depth is reached; S5. Laying of interlayer: a interlayer is set between the inner well wall body and the outer well wall as needed. The interlayer is a plastic board or the interface between new and old concrete; S6. Construction of the inner well wall body and watertight wall ring: The inner well wall body and watertight wall ring are continuously cast from bottom to top to form an integrated structure, and 8 to 12 grouting pipes are pre-buried in the circumference at intervals of no more than 20m along the vertical direction for grouting in the interlayer later; the inner well wall body is designed in sections according to the properties of the aquifer and geological conditions, and is divided into the inner well wall body corresponding to the weak aquifer and the inner well wall body corresponding to the strong aquifer. Its thickness, material and structure can be constructed differently according to the hydrological and geological conditions; S7. Grouting construction in the interlayer. After the construction of the main body of the inner well wall and the waterproof wall ring is completed, use pre-buried or drilled grouting pipes as needed to inject micro-expansion slurry into the interlayer between the inner and outer well walls. The final grouting pressure of each hole should reach the design pressure. According to construction needs, a waterproof wall ring can also be added in the aquifer to reduce the vertical flow range of the slurry in the interlayer and improve the grouting quality.

[0025] Specifically, the interlayer spacing and the number of holes per layer in step S7 are the same as the specifications and arrangement of the grouting pipes pre-buried in step S5.

[0026] In order to develop a wellbore structure and construction method based on the optimization of formation water-rich segmentation, a numerical simulation study was carried out. The 1 / 4 plane strain model was established by using the finite element software ANSYS. The geometric model is as follows: Figure 3-Figure 14 Shown: Inner radius of inner well wall , inner well wall thickness , the outer radius of the inner well wall , the outer wall thickness , the outer radius of the outer well wall , frozen wall thickness , frozen wall outer radius , after calculation, when the outer boundary of the model is greater than The influence of the far-field boundary can be eliminated when , so the outer radius of the surrounding rock in the model is taken as . Elastic modulus of the inner wellbore wall in water-rich rock formations , Poisson's ratio , elastic modulus of the outer wellbore wall , Poisson's ratio , elastic modulus of the frozen wall , Poisson's ratio , elastic modulus of surrounding rock , Poisson's ratio The calculated depth of the formation is , the horizontal initial stress is calculated according to Heim's formula , vertical initial stress , the excavation unloading rate of the frozen wall is , the pore water pressure coefficient of the outer wellbore wall .

[0027] According to the symmetry of the model, radial displacement constraints are imposed at infinity on the outer boundary of the surrounding rock, and symmetry constraints are set on the corresponding truncation boundaries. The unit type of the model is the high-order two-dimensional 8-node pore pressure fluid-solid coupling solid unit CPT213, and the contact surfaces between the inner boundary of the frozen wall and the outer boundary of the wellbore are set using Contact172 units and Target169 units, respectively.

[0028] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0029] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A wellbore structure based on segmented optimization of formation water-richness, characterized by: It comprises an inner well wall body (11) corresponding to a weak aquifer, an inner well wall body (12) corresponding to a strong aquifer, and a water-blocking wall ring (13), wherein the inner well wall body (11) corresponding to the weak aquifer, the inner well wall body (12) corresponding to the strong aquifer, and the water-blocking wall ring (13) are integrally cast and formed, and the inner well wall body (11) corresponding to the weak aquifer and the inner well wall body (12) corresponding to the strong aquifer are separated by the water-blocking wall ring (13); An outer well wall (2) is cast between the upper and lower water-blocking wall circles (13).

2. The wellbore structure based on segmented optimization of formation water-richness according to claim 1, characterized in that: A temporary support (14) is installed on the outer side wall of the waterproof wall ring (13), and the temporary support (14) is connected to the waterproof layer (6).

3. The wellbore structure based on segmented optimization of formation water-richness according to claim 2, characterized in that: The temporary support (14) adopts hanging nets and / or anchor rods.

4. The wellbore structure based on segmented optimization of formation water-richness according to claim 2, characterized in that: The inner well wall body (11) corresponding to the weak aquifer corresponds to the weak aquifer (4), and the inner well wall body (12) corresponding to the strong aquifer corresponds to the strong aquifer (5).

5. The wellbore structure based on segmented optimization of formation water-richness according to claim 4, characterized in that: The wall thickness of the inner well wall body (11) corresponding to the weak aquifer is smaller than the wall thickness of the inner well wall body (12) corresponding to the strong aquifer.

6. The wellbore structure based on segmented optimization of formation water-richness according to claim 5, characterized in that: The outer side walls of the inner well wall body (11) corresponding to the weak aquifer and the inner well wall body (12) corresponding to the strong aquifer are cast with the outer well wall (2), and an interlayer (3) is installed between the outer side walls of the inner well wall body (11) corresponding to the weak aquifer and the inner well wall body (12) corresponding to the strong aquifer and the side walls of the outer well wall (2).

7. The wellbore structure based on segmented optimization of formation water-richness according to claim 6, characterized in that: The interlayer (3) is made of a plastic board, a foam board or a new and old concrete interface.

8. A method for constructing a wellbore structure based on segmented optimization of formation water-richness, used for constructing a wellbore structure based on segmented optimization of formation water-richness according to any one of claims 1 to 7, characterized in that: The steps include: S1. Well inspection hole detection determines the well wall structure. The position and shape of the water-blocking wall ring are determined according to the well wall structure requirements and the hydrological and geological conditions of the wellbore passing through the stratum. The shape of the water-blocking wall ring is achieved by adjusting the template and its blade foot used in the casting process of the outer well wall; S2, start the construction of the outer shaft wall, dig and cast the outer shaft wall in sections from top to bottom; S3, reserved pouring area construction, when the outer well wall is constructed to the position of the water-blocking wall ring determined in S1, a temporary support method is used to reserve the pouring area of ​​the water-blocking wall ring; S4, the outer well wall is constructed to a predetermined depth, and the operations of steps S2 and S3 are repeated until the predetermined depth is reached; S5. Laying of interlayer: a interlayer is set between the inner well wall body and the outer well wall as needed. The interlayer is a plastic board or the interface between new and old concrete; S6. Construction of the inner well wall body and watertight wall ring: The inner well wall body and watertight wall ring are continuously cast from bottom to top to form an integrated structure, and 8 to 12 grouting pipes are pre-buried in the circumference at intervals of no more than 20m along the vertical direction for grouting in the interlayer later; the inner well wall body is designed in sections according to the properties of the aquifer and geological conditions, and is divided into the inner well wall body corresponding to the weak aquifer and the inner well wall body corresponding to the strong aquifer. Its thickness, material and structure can be constructed differently according to the hydrological and geological conditions; S7. Grouting construction in the interlayer. After the construction of the main body of the inner well wall and the waterproof wall ring is completed, use pre-buried or drilled grouting pipes as needed to inject micro-expansion slurry into the interlayer between the inner and outer well walls. The final grouting pressure of each hole should reach the design pressure. According to construction needs, a waterproof wall ring can also be added in the aquifer to reduce the vertical flow range of the slurry in the interlayer and improve the grouting quality.

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