A shaft lining structure and construction method with segmented optimization based on the water-richness of strata

Abstract

The present invention discloses a shaft wall structure and construction method optimized by section based on the water richness of strata, which relates to the technical field of mine construction engineering. It includes the inner shaft wall main body of the strong aquifer, the inner shaft wall main body of the weak aquifer, and the water isolation wall ring. The inner shaft wall main body of the strong aquifer, the inner shaft wall main body of the weak aquifer, and the water isolation wall ring are integrally cast, and the inner shaft wall main body of the strong aquifer and the inner shaft wall main body of the weak aquifer are separated by the water isolation wall ring; the outer shaft wall is cast between the upper and lower water isolation wall rings. The shaft wall structure and construction method optimized by section based on the water richness of strata in the present invention have simple construction technology for the shaft wall structure, good overall water sealing performance, and can realize targeted sectional design and improvement of the shaft wall structure in the vertical direction of deep large vertical shafts, optimize the shaft wall structure in deep water-rich rock strata, and reduce the cost of the shaft.

Description

Technical Field

[0001] The present invention relates to the technical field of mine construction engineering, and particularly relates to a shaft wall structure and construction method optimized in segments based on the water richness of strata. Background Art

[0002] For deep and water-rich rock formations, high-benefit water sealing remains a key and difficult problem in vertical shaft construction. At present, although double-layer shaft walls or double-layer composite shaft walls can achieve excellent water-sealing performance in deep and water-rich rock formations, the two shaft wall structures and their construction technologies completely follow the shaft sinking technologies and construction experiences in deep alluvial layers in the central and eastern regions, and no targeted research and improvement have been carried out according to the hydrogeological conditions of water-rich rock formations, resulting in the current design theories, methods, specifications and standards of frozen shaft walls, and even non-frozen shafts, being difficult to scientifically guide the construction of deep and large vertical shaft shafts in deep water-rich rock formations; the shaft wall structures and parameters designed according to the current specifications do not adapt to the characteristics of deep water-rich rock formations, causing problems such as large shaft wall thickness, easy cracking, poor waterproof performance, as well as large shaft sinking engineering quantities and difficulties, large investment and long construction periods.

[0003] For the double-layer shaft wall or double-layer composite shaft wall structure in deep overburden, the outer shaft wall is mainly used to resist the freezing pressure and construction loads, and the inner shaft wall is designed to resist the full water pressure. The inner and outer shaft walls jointly bear the permanent ground pressure, and a relatively perfect design theory has been formed in a large number of engineering practices. However, for the double-layer shaft wall or double-layer composite shaft wall in water-rich rock formations, since the frozen rock strength is relatively high and the freezing wall is basically in an elastic state during tunneling, the outer shaft wall can be taken as an empirical value. According to the current specifications, the inner shaft wall should be calculated according to the full water pressure. As the thickness of the water-rich rock formations that deep vertical shaft shafts in China need to pass through is getting larger and larger, a considerable number of shafts will pass through rock formations with a depth of more than 1000 to 1500 m. Under such conditions, the design method of the frozen shaft wall structure in the bedrock section still follows the design method of the frozen shaft wall in the overburden layer, and is designed according to the current "Design Code for Coal Mine Vertical Shaft Shafts and Chambers". When using a double-layer composite shaft wall structure, for some large-diameter deep shaft shafts, even when C80 concrete is used for support, the total thickness of the shaft wall will still exceed 3.0 m (where the thickness of the inner shaft wall exceeds 2.5 m). The utilization rate of the shaft tunneling section (the ratio of the net cross-sectional area of the shaft to the tunneling cross-sectional area) is less than 30%. Therefore, the construction cost of the bedrock section composite shaft wall tunneling and lining is necessarily very high, and it also greatly increases the construction costs of projects such as shaft freezing, and prolongs the construction period of shaft construction. As the depth of shaft construction increases, the double-layer shaft wall or double-layer composite shaft wall structure becomes more and more unreasonable.

[0004] How to develop a shaft wall structure and construction method optimized in segments based on the water richness of strata, reduce the thickness of the shaft wall, improve the utilization rate of the shaft tunneling section, and thus reduce the project cost has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0005] The object of the present invention is to provide a shaft lining structure and construction method optimized by section based on the water-richness of the formation, so as to solve the problems listed in the background art.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A shaft lining structure and construction method optimized by section based on the water-richness of the formation of the present invention includes an inner shaft lining body in a strong aquifer, an inner shaft lining body in a weak aquifer and a water-proof wall ring. The inner shaft lining body in the strong aquifer, the inner shaft lining body in the weak aquifer and the water-proof wall ring are integrally cast, and the inner shaft lining body in the strong aquifer and the inner shaft lining body in the weak aquifer are separated by the water-proof wall ring;

[0008] An outer shaft lining is cast between the upper and lower water-proof wall rings.

[0009] Preferably, a temporary support is installed on the outer side wall of the water-proof wall ring, and the temporary support is connected to the water-proof layer.

[0010] Preferably, the temporary support adopts a wire mesh and / or a bolt.

[0011] Preferably, the inner shaft lining body in the strong aquifer corresponds to the strong aquifer, and the inner shaft lining body in the weak aquifer corresponds to the weak aquifer.

[0012] Preferably, the wall thickness of the inner shaft lining body in the strong aquifer is greater than the wall thickness of the inner shaft lining body in the weak aquifer.

[0013] Preferably, the outer shaft lining is cast on the outer side walls of the inner shaft lining body in the strong aquifer and the inner shaft lining body in the weak aquifer, and a sandwich layer is installed between the outer side walls of the inner shaft lining body in the strong aquifer, the inner shaft lining body in the weak aquifer and the side wall of the outer shaft lining.

[0014] Preferably, the sandwich layer adopts a plastic board, a foam board or an interface between new and old concrete.

[0015] A construction method for a shaft lining structure optimized by section based on the water-richness of the formation includes the following steps:

[0016] S1. Detect the shaft lining structure through a shaft inspection hole, determine the position and shape of the water-proof wall ring according to the requirements of the shaft lining structure and the hydrogeological conditions of the formation penetrated by the shaft, and the shape of the water-proof wall ring is realized by adjusting the formwork and its cutting edge used in the process of casting the outer shaft lining;

[0017] S2. Start the construction of the outer shaft lining, and excavate and cast the outer shaft lining section by section from top to bottom;

[0018] 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;

[0019] 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;

[0020] 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;

[0021] 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 of the weak aquifer and the inner well wall body of the strong aquifer. Its thickness, material and structure can be constructed differently according to the hydrological and geological conditions;

[0022] 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.

[0023] Compared with the prior art, the beneficial technical effects of the present invention are:

[0024] 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

[0025] The present invention will be further described below in conjunction with the accompanying drawings.

[0026] Figure 1 Schematic cross-sectional view of a shaft wall structure optimized in segments based on the water-richness of the formation according to the present invention;

[0027] Figure 2 Flowchart of the construction method of a shaft wall structure optimized in segments based on the water-richness of the formation according to the present invention;

[0028] Figure 3 Radial stress nephogram of the inner shaft wall in the service stage according to the present invention;

[0029] Figure 4 Circumferential stress nephogram of the inner shaft wall in the service stage according to the present invention;

[0030] Figure 5 Comparison diagram of the finite element and analytical solutions of the surrounding rock stress in the tunneling stage according to the present invention;

[0031] Figure 6 Comparison diagram of the finite element and analytical solutions of the surrounding rock displacement in the tunneling stage according to the present invention;

[0032] Figure 7 Comparison diagram of the finite element and analytical solutions of the freezing wall stress in the tunneling stage according to the present invention;

[0033] Figure 8 Comparison diagram of the finite element and analytical solutions of the freezing wall displacement in the tunneling stage according to the present invention;

[0034] Figure 9 Comparison diagram of the finite element and analytical solutions of the outer shaft wall stress in the masonry stage of the outer shaft wall according to the present invention;

[0035] Figure 10 Comparison diagram of the finite element and analytical solutions of the outer shaft wall displacement in the masonry stage of the outer shaft wall according to the present invention;

[0036] Figure 11 Comparison diagram of the finite element and analytical solutions of the outer shaft wall stress in the service stage according to the present invention;

[0037] Figure 12 Comparison diagram of the finite element and analytical solutions of the outer shaft wall displacement in the service stage according to the present invention;

[0038] Figure 13 Comparison diagram of the finite element and analytical solutions of the inner shaft wall stress in the service stage according to the present invention;

[0039] Figure 14 Comparison diagram of the finite element and analytical solutions of the inner shaft wall displacement in the service stage according to the present invention.

[0040] Explanation of reference numerals: 11, main body of the inner shaft wall in the weak aquifer; 12, main body of the inner shaft wall in the strong aquifer; 13, water isolation wall ring; 14, temporary support; 2, outer shaft wall; 3, interlayer; 4, weak aquifer; 5, strong aquifer; 6, water isolation layer. Detailed implementation manners

[0041] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to 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.

[0042] As Figure 1 shown, a shaft lining structure optimized in sections based on the water richness of the formation includes an inner shaft lining main body 11 for the weak aquifer, an inner shaft lining main body 12 for the strong aquifer, and a water isolation wall ring 13. The inner shaft lining main body 11 for the weak aquifer, the inner shaft lining main body 12 for the strong aquifer, and the water isolation wall ring 13 are integrally cast, and the inner shaft lining main body 11 for the weak aquifer and the inner shaft lining main body 12 for the strong aquifer are separated by the water isolation wall ring 13; the inner shaft lining main body 11 for the weak aquifer corresponds to the weak aquifer 4, and the inner shaft lining main body 12 for the strong aquifer corresponds to the strong aquifer 5;

[0043] An outer shaft lining 2 is cast between the upper and lower water isolation wall rings 13. A temporary support 14 is installed on the outer side wall of the water isolation wall ring 13, and the temporary support 14 is connected to the water isolation layer 6; by means of the water isolation wall ring 13 in direct contact with the water isolation layer 6, the connection between different aquifers in the vertical direction is cut off, and at the same time, the formations with different hydrogeological conditions are segmented and blocked in a targeted manner, and the shaft lining and the penetrated formation are segmented and classified structurally; based on this shaft lining structure, in the process of shaft lining design, the structure and materials of each section of the shaft lining can be reasonably optimized according to the hydrogeological conditions of the penetrated formation, and strategies for releasing or resisting the water pressure between the inner and outer shaft linings of each section can be selectively implemented, providing technical support for reducing the thickness of the inner shaft lining.

[0044] Specifically, the temporary support 14 adopts wire meshing and / or anchor bolts.

[0045] Specifically, the wall thickness of the inner shaft lining main body 11 for the weak aquifer is smaller than the wall thickness of the inner shaft lining main body 12 for the strong aquifer.

[0046] Specifically, the outer shaft lining 2 is cast on the outer side walls of the inner shaft lining main body 11 for the weak aquifer and the inner shaft lining main body 12 for the strong aquifer, and a sandwich layer 3 is installed between the outer side walls of the inner shaft lining main body 11 for the weak aquifer, the inner shaft lining main body 12 for the strong aquifer and the side wall of the outer shaft lining 2.

[0047] Specifically, the sandwich layer 3 adopts a plastic board, a foam board or an interface between new and old concrete.

[0048] As Figure 2 shown, a construction method for a shaft lining structure optimized in sections based on the water richness of the formation includes the following steps:

[0049] S1. Detect the wellbore structure through inspection holes, determine the position and shape of the water - proof wall ring according to the requirements of the wellbore structure and the hydro - geological conditions of the strata penetrated by the wellbore. The shape of the water - proof wall ring is achieved by adjusting the formwork and its cutting edge used in the process of pouring the outer wellbore;

[0050] S2. Start the construction of the outer wellbore, excavate and pour the outer wellbore section by section from top to bottom;

[0051] S3. Construction of the reserved pouring area. When the outer wellbore construction reaches the position of the water - proof wall ring determined in S1, use temporary support to reserve the pouring area of the water - proof wall ring;

[0052] S4. When the outer wellbore construction reaches the predetermined depth, repeat the operations in the above S2 and S3 steps until the construction reaches the predetermined depth;

[0053] S5. Laying of the interlayer. Set an interlayer between the main body of the inner wellbore and the outer wellbore as needed. The interlayer is a plastic board or the interface between new and old concrete;

[0054] S6. Construction of the main body of the inner wellbore and the water - proof wall ring. Continuously pour the main body of the inner wellbore and the water - proof wall ring from bottom to top to make them an integrated structure, and embed 8 - 12 grouting pipes circumferentially at intervals of no more than 20 m vertically for later grouting in the interlayer. The main body of the inner wellbore is designed in a targeted segmented manner according to the properties of the aquifer and the geological conditions, and is divided into the main body of the inner wellbore in the weak aquifer and the main body of the inner wellbore in the strong aquifer. Its thickness, material and structure can be constructed differently according to the hydro - geological conditions;

[0055] S7. Grouting construction in the interlayer. After the construction of the main body of the inner wellbore and the water - proof wall ring is completed, inject micro - expanding slurry into the interlayer between the inner and outer wellbores using the pre - embedded or newly installed grouting pipes drilled as needed, and the final grouting pressure of each hole should reach the design pressure. According to the construction requirements, a water - proof 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.

[0056] Specifically, the layer spacing and the number of holes in each layer in step S7 are the same as those of the pre - embedded grouting pipes and their specifications and layouts in step S5.

[0057] To develop a wellbore structure and construction method optimized by segment according to the water - richness of the strata, a numerical simulation study was carried out. A 1 / 4 plane - strain model was established through the finite - element software ANSYS, and its geometric model is as follows Figures 3 - 14As shown: the inner radius of the inner shaft wall \(r_0 = 3.25m\), the thickness of the inner shaft wall \(\delta_1 = 1.6m\), the outer radius of the inner shaft wall \(r_1 = 4.85m\), the thickness of the outer shaft wall \(\delta_2 = 0.4m\), the outer radius of the outer shaft wall \(r_2 = 5.25m\), the thickness of the frozen wall \(\delta_3 = 7m\), the outer radius of the frozen wall \(r_3 = 12.25m\). After calculation, when the outer boundary of the model is greater than \(16r_3\), the influence of the far-field boundary can be eliminated. Therefore, the outer radius of the surrounding rock in the model is taken as \(r_4 = 196m\). The elastic modulus \(E\) of the inner shaft wall in the water-rich rock stratum n \(= 35GPa\), Poisson's ratio \(\mu\) n \(= 0.2\), the elastic modulus \(E\) of the outer shaft wall w \(= 25GPa\), Poisson's ratio \(\mu\) w \(= 0.2\), the elastic modulus \(E\) of the frozen wall f \(= 15GPa\), Poisson's ratio \(\mu\) f \(= 0.2\), the elastic modulus \(E\) of the surrounding rock s \(= 10GPa\), Poisson's ratio \(\mu\) s \(= 0.33\). The calculation depth of the stratum is \(H = 800m\). The horizontal initial stress is calculated according to Heim's formula \(p\) h \(= 10.4MPa\), the vertical initial stress \(p\) v \(= 20.8MPa\). The excavation unloading rate of the frozen wall is taken as \(\alpha = 0.75\), and the pore water pressure coefficient \(\omega\) of the outer shaft wall w \(= 0.8\).

[0058] According to the symmetry of the model, a radial displacement constraint is applied at infinity on the outer boundary of the surrounding rock, and a symmetry constraint is set for the corresponding truncated boundary. The element type of the model is selected as the high-order two-dimensional 8-node pore pressure fluid-solid coupling solid element CPT213. The contact surfaces are set for the inner boundary of the frozen wall and the outer boundary of the shaft wall by using Contact172 element and Target169 element respectively.

[0059] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0060] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall 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 a weak aquifer inner well wall body (11), a strong aquifer inner well wall body (12) and a water-blocking wall ring (13), wherein the weak aquifer inner well wall body (11), the strong aquifer inner well wall body (12) and the water-blocking wall ring (13) are integrally cast and formed, and the weak aquifer inner well wall body (11) and the strong aquifer inner well wall body (12) 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); The outer side wall of the waterproof wall ring (13) is installed with a temporary support (14), and the temporary support (14) is connected to the waterproof layer (6); The outer side walls of the weak aquifer inner well wall body (11) and the strong aquifer inner well wall body (12) are cast with the outer well wall (2), and an interlayer (3) is installed between the outer side walls of the weak aquifer inner well wall body (11) and the strong aquifer inner well wall body (12) and the side walls of the outer well wall (2); The interlayer (3) is made of a plastic board, a foam board or a new and old concrete interface.

2. The wellbore structure based on segmented optimization of formation water-richness according to claim 1, characterized in that: The temporary support (14) adopts hanging nets and / or anchor rods.

3. The wellbore structure based on segmented optimization of formation water-richness according to claim 1, characterized in that: The inner layer well wall body (11) of the weak aquifer corresponds to the weak aquifer (4), and the inner layer well wall body (12) of the strong aquifer corresponds to the strong aquifer (5).

4. The wellbore structure based on segmented optimization of formation water-richness according to claim 3 is characterized by: The wall thickness of the inner well wall body (11) of the weak aquifer is smaller than the wall thickness of the inner well wall body (12) of the strong aquifer.

5. 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 4, 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 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 of the weak aquifer and the inner well wall body of 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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