Underground gravity energy storage shaft and chamber spatial arrangement structure and design method

Abstract

The invention discloses an underground gravity energy storage shaft and chamber spatial arrangement structure and a design method. The underground gravity energy storage shaft and chamber spatial arrangement structure comprises a vertical shaft; a weight block storage chamber group; the weight block storage chamber groups are arranged on the two sides of the vertical shaft with the vertical shaft as the symmetry axis, and the weight block storage chamber group on each side comprises five weight block storage chambers arranged in parallel. The weight block transportation chamber group is used for transporting weight blocks among the weight block storage chambers; the weight block transportation chamber group comprises four parallel weight block transportation chambers, and the weight block transportation chambers are perpendicular to the weight block storage chambers; the head end and the tail end of the weight block transportation chamber group on each side of the vertical shaft are respectively connected with a weight block transportation chamber; and the connecting section chamber is used for connecting the weight block transportation chamber close to the side of the vertical shaft with the vertical shaft. According to the scheme, the difficulty and cost of excavation construction and maintenance of the chamber can be reduced while the requirements for gravity energy storage transportation and storage capacity can be well met.

Description

Technical Field

[0001] The present invention belongs to the technical field of vertical shaft type gravity energy storage, and specifically relates to an underground gravity energy storage shaft and chamber space layout structure and design method. Background Art

[0002] The shaft gravity energy storage system is a gravity energy storage system based on the shaft. The shaft is a well-shaped pipe with an upright cave wall, so that the height difference between the shaft and the upper and lower parts is used as a channel for transporting energy storage weight blocks. When storing energy, the weight blocks are lifted from a low place (lower warehouse) to a high place (upper warehouse) for storage, and the electrical energy is converted into gravitational potential energy. When discharging, the weight blocks are lowered from a high place (upper warehouse) to a low place (lower warehouse), and the gravitational potential energy is first converted into kinetic energy, and then converted into electrical energy through a generator. Among them, the lower warehouse is generally located underground and has a chamber structure for storing and transporting weight blocks. The chamber is a horizontal tunnel with a large cross-section and a short length that does not directly lead to the surface exit.

[0003] The gravity energy storage underground chamber is located in the deep underground space, in a complex mechanical environment of "high ground stress, high ground temperature, high osmotic pressure and strong heavy-load transportation disturbance", which leads to significant differences in the mechanical behavior, energy evolution law and damage distribution of the surrounding rock of the chamber and the tunnel and the shallow underground space engineering. The support means used in the shallow underground space engineering partially or completely fail in this scenario, increasing the possibility of deformation and instability of the surrounding rock and dynamic disasters. In addition, the service life of the gravity energy storage warehouse is long, and conventional support means are difficult to cope with mechanical phenomena such as creep and rheology on a long time scale. In order to meet the service capacity requirements of gravity energy storage, it is necessary to excavate about 30,000 cubic meters of underground rock mass. The large-scale empty top of the underground space will lead to the concentration of overburden stress, which may cause impact instability and disaster. Therefore, it is necessary to verify the stress concentration of the surrounding rock of the underground chamber. In addition, gravity energy storage requires the periodic transportation of heavy-loaded energy storage blocks in underground space. The transportation process will impose cyclic dynamic and static loads on the surrounding rocks of tunnels and chambers. The long-term operation of gravity energy storage units will cause fatigue damage to the surrounding rocks of tunnels and chambers, which will lead to surrounding rock damage, crack field development and expansion, and surrounding rock instability disasters. Therefore, it is of great significance to study the laws of surrounding rock damage and instability disasters under the conditions of dynamic and static load disturbances in deep gravity energy storage warehouses, and optimize the design of support methods in combination with actual engineering needs to ensure the long-term safe and stable operation of gravity energy storage units.

[0004] In recent years, the number of publicly published data and literature shows that the layout of underground energy storage facilities and other related fields are becoming a research hotspot for domestic and foreign scientific research institutions and related enterprises. The current mainstream research on the layout of underground energy storage facilities includes underground compressed gas energy storage and gravity energy storage.

[0005] For example, patent CN116992529A relates to a layout design method for a hard rock underground compressed gas energy storage chamber group, which includes the following steps: obtaining the engineering geological parameters of the chamber site; comprehensively considering the maximum air internal pressure, and determining the safe burial depth in combination with the engineering geological parameters; selecting multiple feasible cavern diameters within the maximum cavern diameter range allowed by the safe burial depth, and establishing a three-chamber model to solve the minimum safe cavern distance; using a quadratic polynomial to fit the relationship between the cavern diameter and the minimum safe cavern distance; determining the reserved distance outside the cavern group, the number of caverns permitted by the land use, and the volume of the gas storage reservoir based on the minimum safe cavern distance and cavern diameter; using the maximum volume of the gas storage reservoir as a criterion, determining the corresponding minimum safe cavern distance, cavern diameter, number of caverns, and reserved distance outside, and obtaining a cavern group layout design scheme in combination with the safe burial depth. However, this method does not consider the impact of the layout of connecting chambers and shafts between storage chambers on the stability of the chamber group. Under complex operating conditions of underground energy storage chambers, the surrounding rock of the connecting chambers and shafts may become unstable, affecting the safe and stable operation of the energy storage system.

[0006] For another example, patent CN118167346A proposes an underground space arrangement system for gravity energy storage and a gravity energy storage system. Among them, the underground space arrangement system for gravity energy storage includes a logistics shaft, a service shaft, a weight storage tunnel and a lifting mechanism. The logistics shaft is used to transport energy storage heavy objects; the logistics shaft and the service shaft are arranged at intervals and extend in the up and down directions; the weight storage tunnel is used to store the energy storage heavy objects; the weight storage tunnel extends in the transverse direction, and the weight storage tunnel intersects with each of the logistics shaft and the service shaft, and the logistics shaft, the weight storage tunnel and the service shaft are connected in sequence to form a ventilation channel; the lifting mechanism is installed in the logistics shaft to transport energy storage heavy objects. This arrangement arranges the energy storage chamber and the shaft in the same vertical plane, does not make full use of the underground space, and this arrangement may lead to the superposition of stresses in chambers and shafts at different levels, resulting in stress concentration, which is not conducive to the long-term safe and stable operation of underground energy storage chambers. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide an underground gravity energy storage shaft and chamber space layout structure and design method, so as to solve the problem that the prior art fails to fully consider the stress distribution in the underground space, the interaction between the heavy block storage chamber group and the lifting shaft, and the disturbance and damage of the underground space excavation on the surrounding rock, and thus the underground gravity energy storage shaft and chamber layout scheme provided are difficult to maintain long-term safe and stable operation under the conditions of ground stress, surrounding rock excavation disturbance and energy storage heavy block cyclic load disturbance. By further optimizing and improving the chamber design, the effect of better balancing the long-term stability of the chamber and the construction cost can be achieved.

[0008] According to the technical solution of the present invention, the present invention provides an underground gravity energy storage shaft and chamber space arrangement structure, including: a vertical shaft, which is used to transport energy storage weights between the ground and the underground chamber; a weight block storage chamber group, which is used to store energy storage weights; the weight block storage chamber group is arranged on both sides of the vertical shaft with the vertical shaft as the symmetry axis, and the weight block storage chamber group on each side includes five weight block storage chambers arranged in parallel. Storage chamber; a weight block transport chamber group, which is used to transport weight blocks between the weight block storage chambers; the weight block transport chamber group includes four parallel weight block transport chambers, and the weight block transport chambers are perpendicular to the weight block storage chambers; the head and tail ends of the weight block transport chamber group on each side of the vertical shaft are connected to a weight block transport chamber; a connecting section chamber, which is used to connect the weight block transport chamber close to the vertical shaft side with the vertical shaft.

[0009] Furthermore, the heavy object block storage chamber group, the heavy object block transport chamber group and the connecting section chamber are all located at the same burial depth level, and are symmetrically distributed as a whole with the vertical shaft as the center.

[0010] Furthermore, the shape of the heavy object block storage chamber is a straight-walled semicircular arch, and two rows of storage racks are arranged horizontally side by side at the bottom of the heavy object block storage chamber. A transport channel for a transport vehicle to pass through is formed in each row of storage racks, and storage positions for placing a row of heavy objects are formed on each row of storage racks.

[0011] Furthermore, the shape of the heavy object block storage chamber is a straight-wall semicircular arch, wherein the ratio of the straight wall height to the semicircular arch radius is in the range of 0.730 to 1.807; the distance between each heavy object block storage chamber is not less than 1.5 times the width of the heavy object block storage chamber.

[0012] Furthermore, the shape of the heavy object block transport chamber is a straight-walled semicircular arch, and chamfers are provided at the right-angle connections between each heavy object block transport chamber and the heavy object block storage chamber.

[0013] Furthermore, the connecting section chamber is perpendicular to the vertical shaft and the heavy object transport chamber, and the connecting section chamber connects the midpoint of the heavy object transport chamber with the bottom of the vertical shaft.

[0014] Furthermore, the shape of the connecting section chamber is a straight-walled semicircular arch, and the lengths of the two connecting section chambers on both sides of the vertical shaft are not less than 17.5m.

[0015] According to the technical solution of the present invention, the present invention also provides a design method for an underground gravity energy storage shaft and a chamber space layout structure, which adopts the underground gravity energy storage shaft and the chamber space layout structure of the present invention, wherein the heavy object block storage chamber, the heavy object block transportation chamber, and the connecting section chamber are all straight-walled semicircular arch chambers; the design method of the underground gravity energy storage shaft and the chamber space layout structure includes the chamber shape optimization design, specifically including the following contents: Taking the radius r of the semicircular arch as the independent variable, several working conditions are designed when the cross-sectional area of ​​the straight-walled semicircular arch chamber is constant; at least four measuring points are arranged on the wall of the straight-walled semicircular arch chamber, including the top middle position of the straight-walled semicircular arch, the bottom middle position of the straight-walled semicircular arch, the bottom corner position of the straight-walled semicircular arch, and the intersection position between the straight wall and the semicircular arch; the horizontal and vertical stress conditions at each measuring point under various working conditions are monitored; based on the monitoring results, the changes of the horizontal normal stress of each measuring point with the radius r of the semicircular arch, as well as the vertical normal stress of each measuring point are analyzed. The variation of the normal stress in the vertical direction with the radius r of the semicircular arch is studied. The section where the second-order derivative mean of the normal stress in the horizontal direction first increases and then decreases is selected as the first range R1, and the section where the second-order derivative mean of the normal stress in the vertical direction first increases and then decreases is selected as the second range R2. The intersection of the first range R1 and the second range R2 is taken as the optimal design range. The ratio of the straight wall height to the semicircular arch radius of each working condition within the optimal design range is calculated to obtain the optimal range of the ratio of the straight wall height to the semicircular arch radius. The range that satisfies the optimal ratio of the straight wall height to the semicircular arch radius is used as the standard for the reasonable design of the straight-wall circular arch chamber shape.

[0016] Compared with the prior art, the beneficial technical effects of the present invention are as follows: 1. In the underground gravity energy storage shaft and chamber space layout structure of the present invention, a heavy object block storage chamber group, a heavy object block transport chamber group and a connecting section chamber are designed, and the number, spacing, shape, size and other aspects of the chambers are optimized, which can better meet the requirements of gravity energy storage transportation and storage capacity while reducing the difficulty and cost of chamber excavation, construction and maintenance.

[0017] 2. In the underground gravity energy storage shaft and chamber space layout structure of the present invention, the vertical shaft is arranged in the stress reduction zone formed by the excavation of the weight block storage chamber and the weight block transport chamber on both sides, which is beneficial to maintaining the long-term safety and stability of the vertical shaft.

[0018] 3. In the underground gravity energy storage shaft and chamber space layout structure of the present invention, the chamber layout spacing takes into account the stress distribution of the surrounding rock of each heavy object storage chamber and the excavation space size. Therefore, the chamber layout scheme proposed by the present invention can better balance the long-term stability of the chamber and the construction cost.

[0019] 4. The design method of the underground gravity energy storage shaft and chamber space layout structure of the present invention fully considers the changes in stress distribution caused by the excavation of the underground gravity energy storage shaft and chamber, and reduces the stress concentration in the surrounding rock as much as possible, thereby reducing the difficulty of excavation and maintenance of the underground gravity energy storage shaft and chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional schematic diagram of an underground gravity energy storage shaft and chamber space layout structure provided by the present invention.

[0021] Figure 2 It is a top view schematic diagram of an underground gravity energy storage shaft and chamber space layout structure provided by the present invention.

[0022] Figure 3a It is a structural schematic diagram of the heavy object block storage chamber provided by the present invention.

[0023] Figure 3b yes Figure 3a Dimensioning drawing of the preferred design.

[0024] Figure 4 It is a curve chart of the relationship between the semicircular arch radius r and the straight wall height h of a straight-wall semicircular arch chamber with the same cross-sectional area.

[0025] Figure 5a It is a diagram of the horizontal displacement detection results of each measuring point under different working conditions in the design method provided by the present invention.

[0026] Figure 5b It is a diagram of the vertical displacement detection results of each measuring point under different working conditions in the design method provided by the present invention.

[0027] Figure 5c It is a diagram of the horizontal normal stress detection results of each measuring point under different working conditions in the design method provided by the present invention.

[0028] Figure 5d It is a diagram of the normal stress detection results of each measuring point in the vertical direction under different working conditions in the design method provided by the present invention.

[0029] Figure 5e It is a diagram of shear stress detection results at each measuring point under different working conditions in the design method provided by the present invention.

[0030] Figure 5f It is a diagram of the arrangement positions of measuring points on a straight-wall semicircular arch chamber in the design method provided by the present invention.

[0031] Figure 6 It is a curve chart showing the variation of the second-order derivative mean of the normal stress in the horizontal and vertical directions at each measuring point in the chamber with the radius of the semicircular arch of the chamber.

[0032] Figures 7a to 7cThe vertical stress cloud diagrams are when the number of heavy object storage chambers is 3, 5, and 7 respectively.

[0033] Figure 8a , Figure 8b Respectively in Figure 7b On this basis, the vertical stress cloud diagram is shown when the length of the connecting section chamber is increased by 20m and 30m.

[0034] Figures 9a to 9d They are the distribution diagrams of the plastic zone when the length of the connecting section chamber increases by 0m, 10m, 20m and 30m respectively.

[0035] Fig.10 It is a schematic diagram of the stress increase area in the heavy object storage chamber on both sides.

[0036] Fig.11 This is the stress distribution diagram on the pillar under different connection section chamber lengths.

[0037] Description of reference numerals in the accompanying drawings: 1. Vertical shaft; 2. Heavy object block storage chamber; 3. Heavy object block transportation chamber; 4. Connecting section chamber; 21. Storage rack; 22. Carrier; 23. Heavy object block; 31. Mother vehicle; 32. Transfer vehicle; 41. Conveyor. DETAILED DESCRIPTION

[0038] The present invention provides an underground gravity energy storage shaft and chamber space layout structure and design method, which solves the problem that the existing technology fails to fully consider the stress distribution of underground space, the interaction between the heavy object storage chamber group and the lifting shaft, and the disturbance and damage of underground space excavation on the surrounding rock, and thus the underground gravity energy storage shaft and chamber layout scheme provided are difficult to maintain long-term safe and stable operation under the conditions of ground stress, surrounding rock excavation disturbance and energy storage heavy object cyclic load disturbance. This scheme further optimizes and improves the chamber design, and the proposed chamber layout spacing takes into account the stress distribution of the surrounding rock of each heavy object storage chamber and the excavation space size, so it can better balance the long-term stability of the chamber and the construction cost.

[0039] See also Figures 1 to 3a An underground gravity energy storage shaft and chamber space layout structure according to one embodiment of the present invention mainly includes the following components.

[0040] A vertical shaft 1 is used to transport energy storage heavy objects (heavy blocks) between the ground (upper warehouse) and the underground chamber (lower warehouse), and is provided with a lifting system for lifting the heavy blocks and a connected power system, thereby realizing the basic function of gravity energy storage power generation. The relevant content is the existing technology and will not be elaborated here.

[0041] The heavy object block storage chamber group is used to store (and transport) energy storage heavy objects. The heavy object block storage chamber group is arranged on both sides of the vertical shaft 1 (generally on both sides in the horizontal direction, such as the left and right sides in the figure) with the vertical shaft 1 as the symmetry axis. The heavy object block storage chamber group on each side includes five heavy object block storage chambers 2 arranged in parallel. This layout and number are the preferred solutions obtained through design research, which will be further explained later.

[0042] The heavy object block transport chamber group is used to transport heavy objects at the position between each heavy object block storage chamber 2 (more specifically, outside the end of each heavy object block storage chamber 2 and in a direction perpendicular to the length of the heavy object block storage chamber 2). The heavy object block transport chamber group includes four parallel heavy object block transport chambers 3, and the heavy object block transport chamber 3 is perpendicular to the heavy object block storage chamber 2. The head end and the tail end of the heavy object block transport chamber group on each side of the vertical shaft 1 are connected with a heavy object block transport chamber 3.

[0043] The connecting section chamber 4 is used to connect the heavy object transport chamber near the side of the vertical shaft 1 with the vertical shaft 1. The connecting section chamber 4 has a transport mechanism such as a conveyor for transporting heavy objects, so that the heavy objects can be transported between the vertical shaft 1 and the heavy object storage chamber 2. The connecting section chamber 4 is two sections located on both sides of the vertical shaft 1. It can be set as a straight channel, and the vertical shaft 1 is located in the middle of its length direction.

[0044] More specifically, see Figure 3aThe shape of the heavy block storage chamber 2 is a straight-walled semicircular arch, which has better mechanical properties and can be used for high-height heavy blocks in the shaft-type gravity energy storage system. The bottom of the heavy block storage chamber 2 is provided with two rows of storage racks 21 arranged side by side in a horizontal direction. Specifically, for example, each row of storage racks 21 includes two rows of support bodies, and the two rows of storage racks 21 share one row of support bodies; each row of storage racks 21 (between the two rows of support bodies) is formed with a transport channel for a carrier 22 to pass through, and each row of storage racks 21 is formed with a storage position for placing a row of heavy blocks 23. The heavy blocks 23 are, for example, placed on two rows of support bodies, and the carrier 22 is located below the heavy blocks 23. The carrier 22 is, for example, an RGV trolley, and the transport channel has a track for the carrier 22 to run. The carrier 22 has a lifting and conveying device on top, so that it can lift the heavy object block 23, move it away from the storage rack 21, and move the heavy object block 23 to the storage rack 21 and then place it on the storage rack 21. This kind of cooperation between the carrier and the heavy object block is a prior art. This scheme mainly optimizes the shape and size of the chamber, and then designs and adopts this scheme of setting two rows of storage racks 21 in a heavy object block storage chamber 2, which can hold two rows of heavy object blocks 23. This scheme can improve the space utilization rate and increase the number of heavy objects, that is, the capacity of energy storage and power generation, while ensuring the long-term stability of the chamber structure. In addition, placing more heavy objects in a chamber also helps to reduce the construction cost of the chamber.

[0045] For the structure on each side of the vertical shaft 1, the heavy object block transport chamber group has a heavy object block transport chamber 3 on the side close to the vertical shaft 1 to connect one end (called the head end) of all the heavy object block storage chambers 2. This heavy object block transport chamber 3 is used to further move the heavy objects transported to the head end from the heavy object block storage chamber 2 to the connecting section chamber 4, which has one or more mother vehicles 31, such as RGV trolleys with a similar structure to the carrier vehicle 22 and equipped with a corresponding row of tracks. The mother vehicle 31 can move to the head end of any heavy object block transport chamber 3, and then hand over the heavy objects with the carrier vehicle 22 in the heavy object block transport chamber 3. The mother vehicle 31 can also move to the connecting section chamber 4, and then hand over the heavy objects with the conveyor 41 therein. The conveyor 41 is used to realize the handover of heavy objects with the lifting container in the vertical shaft 1. The heavy object transport chamber group also has another heavy object transport chamber 3 on the side away from the vertical shaft 1, which connects the other end (called the tail end) of all the heavy object storage chambers 2. The other heavy object transport chamber 3 has one or more transfer vehicles 32, such as RGV trolleys with a similar structure to the carrier 22, and is equipped with a corresponding track. The transfer vehicle 32 can move to the tail end of any heavy object transport chamber 3, and then the carrier 22 can move to the top of the transfer vehicle 32, and the transfer vehicle 32 transports the carrier 22 to the tail end of other heavy object transport chambers 3 (transportation channels), thereby realizing the work of transporting the carrier 22 between the heavy object storage chambers 2 (between transport channels). By adopting this scheme, there is no need to set up a carrier 22 in each transport channel, which can avoid the idleness of the carrier 22, improve equipment utilization and reduce construction costs.

[0046] Preferably, the heavy object block storage chamber group, the heavy object block transport chamber group and the connecting section chamber 4 are all located at the same buried depth level, and are symmetrically distributed around the vertical shaft 1. This solution arranges the shaft in the stress reduction zone formed by the excavation of the heavy object block storage chamber and the heavy object block transport chamber on both sides, which is conducive to maintaining the long-term safety and stability of the vertical shaft.

[0047] The connecting section chamber 4 is perpendicular to the vertical shaft 1 and the heavy block transport chamber 3. The connecting section chamber 4 connects the midpoint of the heavy block transport chamber 3 with the bottom of the vertical shaft 1. This structure is more regular and convenient for the construction of the chamber and the automatic transportation of heavy blocks during energy storage and power generation.

[0048] The shape of the heavy object transport chamber 3 is also preferably a straight-walled semicircular arch, and chamfers are provided at the right-angle connections between each heavy object transport chamber 3 and the heavy object storage chamber 2. This structure can avoid excessive local stress and also contribute to the long-term stability of the underground chamber.

[0049] The shape of the connecting section chamber 4 is also preferably a straight-walled semicircular arch, and the lengths of the two connecting section chambers 4 on both sides of the vertical shaft 1 are not less than 17.5m. The shape of the heavy object storage chamber 2 is a straight-walled semicircular arch, wherein the ratio of the straight wall height to the semicircular arch radius is in the range of 0.730 to 1.807; the distance between each heavy object storage chamber 2 is not less than 1.5 times the width of the heavy object storage chamber 2. This size is a preferred solution obtained through design research and will be further described later.

[0050] Based on the underground gravity energy storage shaft and chamber space layout structure described in the present invention, the present invention provides a design method for an underground gravity energy storage shaft and chamber space layout structure, wherein the heavy object block storage chamber, the heavy object block transport chamber, and the connecting section chamber are all straight-walled semicircular arch chambers; the design method of the underground gravity energy storage shaft and chamber space layout structure includes chamber shape optimization design, specifically including the following contents.

[0051] The cross-sectional area of ​​a straight-walled semicircular arch chamber is determined by the radius r of the semicircular arch and the height h of the straight wall. When the cross-sectional area remains unchanged, the relationship between the two is, for example, Figure 4 shown.

[0052] Taking the radius r of the semicircular arch as the independent variable, several working conditions are designed when the cross-sectional area of ​​the straight-wall semicircular arch chamber is constant. For example, six working conditions are designed as shown in the following table.

[0053] Table 1 Chamber cross-section shape working conditions

[0054] like Figure 5f As shown, at least four measuring points (four measuring points in this embodiment) are arranged on the wall surface of the straight wall semicircular arch chamber, and the measuring point positions include the top middle position of the straight wall semicircular arch (P1), the bottom middle position of the straight wall semicircular arch (P4), the bottom corner position of the straight wall semicircular arch (P3), and the intersection position between the straight wall and the semicircular arch (P2); the horizontal and vertical stress conditions and displacement changes at each measuring point under various working conditions are monitored, and the results are shown as follows: Figure 5a to Figure 5e shown.

[0055] Depend on Figure 5a It can be seen from the monitoring results of each point that the horizontal displacement of measuring point P2 is the largest, followed by measuring point P3. Since measuring points P1 and P4 are on the central axis of the chamber, no horizontal displacement occurs. As the width of the chamber (i.e., the radius r of the semicircular arch, i.e., the span of the chamber) increases and the height decreases, the horizontal displacement of measuring points P2 and P3 gradually decreases. This shows that under the condition that the cross-sectional area of ​​the chamber remains unchanged, reducing the height of the straight wall of the chamber is beneficial to maintaining the stability of the surrounding rock on both sides.

[0056] Depend on Figure 5bIt can be seen that as the width of the chamber increases and the height decreases, the vertical displacement of the measuring point P3 decreases, while the displacements (absolute values) of the other three measuring points P1, P2, and P4 increase. This shows that increasing the span of the chamber will reduce the vertical stability of the surrounding rock of the chamber. For measuring point P1, it gradually moves downward; for measuring point P4, it gradually moves upward; that is, the roof deformation and floor heave phenomenon occur.

[0057] Depend on Figure 5c It can be seen that for each measuring point, as the span of the chamber increases and the height decreases, the absolute value of the normal stress in the horizontal direction decreases to varying degrees. The change at measuring point P2 is not significant, and the change degrees of measuring points P1 and P4 are basically the same. Measuring point P3 decreases significantly when the radius of the semicircular arch of the chamber increases from 6m to 7m.

[0058] Depend on Figure 5d It can be seen that for measuring points P1 and P4, as the width of the chamber increases and the height decreases, the absolute value of the normal stress in the vertical direction gradually decreases. For measuring point P3, as the width of the chamber increases, the normal stress in the vertical direction decreases to a certain extent when the radius of the semicircular arch of the chamber increases from 5m to 6m, and then increases significantly when it increases from 6m to 7m.

[0059] Depend on Figure 5e It can be seen that, except for measuring point P2, the shear stress of other measuring points does not change significantly with the increase of chamber width. The shear stress of measuring point P2 decreases first and then increases with the increase of chamber width, and its absolute value is the smallest when the radius of the semicircular arch is about 7.5m.

[0060] See also Figure 6 Based on the above monitoring results, the main consideration is to analyze the changes of the horizontal normal stress of each measuring point with the semicircular arch radius r, and the changes of the vertical normal stress of each measuring point with the semicircular arch radius r. The first range R1 is selected where the second-order derivative mean of the horizontal normal stress first increases and then decreases, and the second range R2 is selected where the second-order derivative mean of the vertical normal stress first increases and then decreases. The intersection of the first range R1 and the second range R2 is taken. Figure 6 In this embodiment, under the conditions of working conditions 2 to 4, the displacement and stress in the horizontal and vertical directions of each measuring point are relatively balanced, which is more conducive to the stability of the surrounding rock of the chamber.

[0061] The second derivative mean of the stress at the measuring point of the surrounding rock reflects the acceleration change of the load borne by the surrounding rock in the horizontal or vertical direction. The stage characterized by the first increase and then decrease of the second derivative mean of stress indicates that the growth rate of the load borne by the surrounding rock is gradually slowing down, indicating that the surrounding rock is transitioning from a stable bearing state to an unstable failure state. Further analysis shows that when the second derivative mean of the vertical positive stress and the second derivative mean of the horizontal positive stress both show an increase first and then a decrease, the intersection of their corresponding time periods (or intervals) represents the critical point of the horizontal and vertical stability of the surrounding rock of the chamber. Within this critical point, the surrounding rock has a high bearing capacity in both the horizontal and vertical directions and can effectively resist significant damage. Once this range is exceeded, the stability of the surrounding rock will drop significantly and unstable failure may occur.

[0062] Furthermore, the ratio of the height of the straight wall to the radius of the semicircular arch of each working condition within the preferred design range is calculated to obtain the preferred range of the ratio of the height of the straight wall to the radius of the semicircular arch, which is 0.730 to 1.807 for this embodiment, thus obtaining a more universal result. The range of the ratio of the height of the straight wall to the radius of the semicircular arch is used as a reasonable standard for the shape design of a straight-walled circular arch chamber, which can be used for the design or verification of the chamber.

[0063] A specific chamber shape and size is as follows Figure 3b As shown (unit: mm), the ratio of the straight wall height to the semicircular arch radius is 1.667, which is within the reasonable standard range obtained by simulation.

[0064] Preferably, the design method also includes a numerical simulation study on the effect of chamber spacing on surrounding rock stability, as follows.

[0065] The numerical model was established based on a tunnel span of 12m and a tunnel height of 12.8m. The excavation was considered in the most unfavorable situation, that is, the cavern was excavated in one go. To eliminate the boundary effect, the model was extended 30m on each side. The model size was 144m long (X direction), 80m wide (Y direction), and 40m high (Z direction). The number of nodes and units in the established model were 363,531 and 344,000, respectively.

[0066] According to relevant regulations: the net spacing between adjacent caverns should be 1 to 2 times the width of the cavern. However, in actual design projects, the cavern spacing should be comprehensively determined by combining domestic and foreign experience and numerical analysis methods. The span ratio of underground caverns built in foreign countries such as Greece, Singapore, South Korea, and Japan is 2.0 to 2.3. The span ratio of underground caverns built in Yantai, Huangdao, Huizhou, etc. in China is 1.5 to 2.0. Therefore, this simulation selected 6 working conditions (as shown in the table below) to simulate the interaction effect of multiple adjacent caverns and the stability of the caverns, and proposed a more reasonable range of cavern spacing.

[0067] Table 2 Simulation calculation conditions of cavern spacing

[0068] Through simulation, the development of plastic zone and the distribution of maximum principal stress in each chamber under different chamber spacing are obtained.

[0069] The simulation results show that as the distance between chambers increases, the mutual disturbance between adjacent chambers gradually decreases. The larger the distance between chambers, the smaller the area of ​​the plastic zone formed near each chamber. The change in the area of ​​the plastic zone on the left and right sides of the chamber is more sensitive to the change in the distance between chambers than the change in the area of ​​the plastic zone in the up and down directions. The degree of decrease in the area of ​​the plastic zone on both sides of the chamber gradually decreases with the increase in distance. When the span ratio is greater than 2, the area of ​​the plastic zone near the chamber remains almost unchanged by continuing to increase or decrease the distance between chambers. At this time, increasing the distance between chambers can no longer play a significant role in maintaining the stability of the surrounding rock of the chamber.

[0070] Therefore, under the premise of ensuring the stability of the surrounding rock of the chamber, the most economical chamber spacing is 2 times the span ratio, that is, the distance between two adjacent heavy block storage chambers is twice the width of the heavy block storage chamber 2. Due to the actual engineering needs, there is a certain degree of flexibility in adjusting the design size according to the situation, and the distance between two adjacent heavy block storage chambers is limited to not less than 1.5 times the width of the heavy block storage chamber 2. For example, the proposed design is that the chamber width is 7.5m and the chamber spacing is 15m, which meets the most stable chamber spacing design.

[0071] Preferably, the design method also includes a study on optimization of energy storage chamber and shaft layout, as follows.

[0072] First, for the overall stress field distribution law under different numbers of chambers (the number of heavy object storage chambers 2 in the heavy object storage chamber group on each side), the vertical stress field cloud diagram of the overall system under different numbers of chambers is analyzed. Figures 7a to 7c As shown in the figure, in general, the number of chambers has little effect on the distribution of overall vertical stress. Affected by the chambers, certain high stress is generated around the shaft. With the increase in the number of chambers, the stress in the high stress area continues to increase. The maximum stress when the number of chambers is 7 is about 5MPa higher than that when the number of chambers is 3, while it is only 2MPa higher when the number of chambers is 5. High stress is also accumulated on the rock pillars between the chambers, mainly concentrated in the first 10m of the chambers. The stress on the pillars between the chambers in the middle is greater than the high stress accumulated on the pillars of the chambers on both sides; with the increase in the number of chambers, the high stress accumulated on the pillars between the chambers also increases.

[0073] Therefore, considering the stability of the overall system, when the number of chambers is 3, the stress between the shaft and the chambers is the lowest, and the stability is better; however, when the number of chambers is 5, the overall stress does not change much, and the transportation efficiency is greatly improved, so the number of chambers is 5. In addition, since a large stress concentration will occur when the intersection of the chambers is a right angle, it is recommended to adjust the right angle at the intersection of the chambers to a rounded corner.

[0074] On the other hand, for the overall stress field distribution law under different lengths of the connection section between the shaft and the lower warehouse (i.e., the length of the connection section chamber 4), the vertical stress cloud diagram around the shaft with different connection section lengths is analyzed, as shown in Figure 7b , Figure 8a , Figure 8b As shown ( Figure 7b As the benchmark working condition, the length of each connection section is 7.5m). It can be seen that with the increase of the length of the connection section, the high stress concentration around the wellbore gradually weakens. Compared with the initial design scheme with a shorter length of the connection section chamber 4, the maximum stress around the wellbore is about 55MPa after the connection section is increased by 10m, which decreases by about 10MPa; when the length of the connection section is increased by 20m and 30m, the stress concentration around the wellbore can be more effectively alleviated, but the effect is limited compared to when the connection section is increased by 10m. Based on this, it is concluded that when the connection section is increased by 10m, that is, when the length of the single-side connection section is 17.5m, the stress concentration of the surrounding rock of the chamber is significantly alleviated. Therefore, the length of the connection section chamber should be greater than 17.5m to avoid stress concentration in the surrounding rock of the chamber, which will lead to instability and failure of the surrounding rock.

[0075] In addition, the overall plastic zone distribution of the transportation system under different connection lengths is analyzed as follows: Figures 9a to 9d , Fig.10 As shown ( Figure 9a As the benchmark working condition, the length of the connection section on each side is 7.5m). It can be seen that as the length of the connection section increases, the range of the plastic zone in the surrounding rock around the wellbore decreases. This is because after the length of the connection section increases, the stress concentration area gradually moves away from the wellbore, which improves the stability of the surrounding rock. But at the same time, as the length of the connection section continues to increase, the plastic zone between the heavy block storage chambers increases. This is because the system as a whole can be divided into two parts with the wellbore as the center, and the mutual influence between the two parts is similar to the mining stress concentration caused by mining. When the connection section increases by 20 or 30m, the position of the chamber will be most affected by the other part, which leads to an increase in the plastic zone. Overall, when the connection section increases by 10m, the range of the plastic zone is lower than that of 20m and 30m.

[0076] Then the stress situation was analyzed. The results showed that different connection section lengths had little effect on the vertical stress distribution around the chamber tunnel. In addition, the stress changes in the surrounding rock under different connection section lengths were analyzed. Fig.11As shown, it can be seen that the force on the pillars between the chambers presents a saddle-shaped distribution. At the same time, as the length of the connecting section increases, the force on the pillars shows a downward trend, and the rate of decline is fastest in the interval from 0m to 10m of the connecting section.

[0077] In summary, considering the size of stress distribution, the width of the plastic zone and the distribution of stress on the pillars, it is a more reasonable choice to increase the length of the connecting section chamber by 10m, that is, the lengths of the two connecting section chambers 4 on both sides of the vertical shaft 1 are not less than 17.5m.

[0078] As a supplementary explanation, since the overall chamber arrangement is symmetrically arranged along the central shaft, the length of the connecting sections on both sides is described as not less than 17.5m, and the length of the connecting section chamber 4 defined does not include the shaft. When the length of the connecting section chamber 4 is 17.5m, the total length of the two connecting section chambers including the shaft (i.e. the distance between the two weight transport chambers 3 on both sides of the shaft) is actually (Unit: m), where R is the shaft radius and w is the width of the connecting section chamber 4.

[0079] In addition, it also includes the stability analysis of chamber tunnels under static loads, which specifically includes the following contents.

[0080] After determining the number of chambers and the length of the connecting sections, a vertical stress of 0.16 MPa is added to the bottom plate of the model to simulate the working condition of a full load of heavy blocks. By comparing the differences in the vertical stress cloud maps after applying static loads, it can be found that the stress added by the weight of the heavy blocks is much smaller than the stress state of the environment in which the chamber is located. Therefore, the impact on the stress distribution around the chamber is small. At the same time, from the perspective of the plastic zone, the width of the overall plastic zone does not change much, indicating that the application of static loads has little effect on the stability of the chambers of the spatial arrangement structure of the present invention.

[0081] In summary, in the underground gravity energy storage shaft and chamber space arrangement structure of the present invention, a weight block storage chamber group, a weight block transport chamber group and a connecting section chamber are designed, and the number, spacing, shape, size and other aspects of the chambers are optimized, which can better meet the requirements of gravity energy storage transportation and storage capacity while reducing the difficulty and cost of chamber excavation, construction and maintenance; the present invention arranges the vertical shaft in the stress reduction zone formed by the excavation of the weight block storage chamber and the weight block transport chamber on both sides, It is beneficial to maintain the long-term safety and stability of the vertical shaft; the spacing of the chamber arrangement of the present invention takes into account the stress distribution of the surrounding rock of each heavy object storage chamber and the size of the excavation space, so the chamber arrangement scheme proposed by the present invention can better balance the long-term stability of the chamber and the construction cost; the design method of the present invention fully considers the stress distribution changes caused by the excavation of the underground gravity energy storage shaft and chamber, and reduces the stress concentration in the surrounding rock as much as possible, thereby reducing the difficulty of excavation and maintenance of the underground gravity energy storage shaft and chamber.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work, such as only modifying the burial depth of the chamber, adjusting the parameters such as the size and shape of the chamber, and not making major changes to the shaft and chamber layout, all belong to the scope of protection of the present invention; for ease of description, only the parts related to the relevant invention are shown in the accompanying drawings. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other; modifying the technical solutions recorded in the aforementioned embodiments, or equivalently replacing some of the technical features therein, does not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An underground gravity energy storage shaft and chamber space arrangement structure, characterized in that: include: A vertical shaft (1) for transporting energy storage heavy objects between the ground and an underground chamber; A weight block storage chamber group, which is used to store energy storage weights; the weight block storage chamber group is arranged on both sides of the vertical shaft (1) with the vertical shaft (1) as a symmetry axis, and the weight block storage chamber group on each side includes five weight block storage chambers (2) arranged in parallel; A weight block transport chamber group is used to transport weight blocks between weight block storage chambers (2); the weight block transport chamber group includes four parallel weight block transport chambers (3), and the weight block transport chambers (3) are perpendicular to the weight block storage chambers (2); a weight block transport chamber (3) is connected to the head end and the tail end of the weight block transport chamber group on each side of the vertical shaft (1); The connecting section chamber (4) is used to connect the heavy object transport chamber close to the side of the vertical shaft (1) and the vertical shaft (1).

2. The underground gravity energy storage shaft and chamber space arrangement structure according to claim 1, characterized in that: The heavy object block storage chamber group, the heavy object block transport chamber group and the connecting section chamber (4) are all located at the same buried depth level and are symmetrically distributed with the vertical shaft (1) as the center.

3. The underground gravity energy storage shaft and chamber space arrangement structure according to claim 1, characterized in that: The heavy object block storage chamber (2) is in the shape of a straight-walled semicircular arch. Two rows of storage racks (21) arranged side by side in a transverse direction are arranged at the bottom of the heavy object block storage chamber (2). A transport passage for a transport vehicle (22) to pass through is formed in each row of storage racks (21). Storage positions capable of placing a row of heavy object blocks (23) are formed on each row of storage racks (21).

4. The underground gravity energy storage shaft and chamber space arrangement structure according to claim 1, characterized in that: The shape of the weight block storage chamber (2) is a straight wall semicircular arch, wherein the ratio of the straight wall height to the semicircular arch radius is in the range of 0.730 to 1.807; and the distance between each weight block storage chamber (2) is not less than 1.5 times the width of the weight block storage chamber (2).

5. The underground gravity energy storage shaft and chamber space arrangement structure according to claim 1, characterized in that: The shape of the heavy object transport chamber (3) is a straight-walled semicircular arch, and a chamfer is provided at the right-angle connection between each heavy object transport chamber (3) and the heavy object storage chamber (2).

6. The underground gravity energy storage shaft and chamber space arrangement structure according to claim 1, characterized in that: The connecting section chamber (4) is perpendicular to the vertical shaft (1) and the heavy object transport chamber (3), and the connecting section chamber (4) connects the midpoint of the heavy object transport chamber (3) with the bottom of the vertical shaft (1).

7. The underground gravity energy storage shaft and chamber space arrangement structure according to claim 1, characterized in that: The connecting section chamber (4) is in the shape of a straight-walled semicircular arch, and the lengths of the two connecting section chambers (4) on both sides of the vertical shaft (1) are not less than 17.5 m.

8. A design method for underground gravity energy storage shaft and chamber space layout structure, characterized in that: It adopts the underground gravity energy storage shaft and chamber space arrangement structure according to claim 1 or 2, wherein the heavy object block storage chamber, the heavy object block transportation chamber, and the connecting section chamber are all straight-walled semicircular arch chambers; the design method of the underground gravity energy storage shaft and chamber space arrangement structure includes chamber shape optimization design, specifically including the following contents: Taking the radius r of the semicircular arch as the independent variable, several working conditions are designed when the cross-sectional area of ​​the straight-walled semicircular arch chamber is constant; at least four measuring points are arranged on the wall surface of the straight-walled semicircular arch chamber, and the measuring point positions include the top middle position of the straight-walled semicircular arch, the bottom middle position of the straight-walled semicircular arch, the bottom corner position of the straight-walled semicircular arch, and the intersection position between the straight wall and the semicircular arch; Monitor the stress conditions in the horizontal and vertical directions at each measuring point under various working conditions; based on the monitoring results, analyze the changes in the horizontal positive stress of each measuring point with the radius r of the semicircular arch, and the changes in the vertical positive stress of each measuring point with the radius r of the semicircular arch, select the section where the second-order derivative mean of the horizontal positive stress first increases and then decreases as the first range R1, and select the section where the second-order derivative mean of the vertical positive stress first increases and then decreases as the second range R2, and take the intersection of the first range R1 and the second range R2 as the optimal design range; calculate the ratio of the straight wall height to the semicircular arch radius of each working condition within the optimal design range, and obtain the optimal range of the ratio of the straight wall height to the semicircular arch radius; and use the range that satisfies the optimal ratio of the straight wall height to the semicircular arch radius as the standard for the reasonable design of the straight-wall circular arch chamber shape.

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