Ultra-deep underground storage structure and construction method thereof

Abstract

According to the ultra-deep underground storage structure reasonable in design and the construction method of the ultra-deep underground storage structure, a series of problems of construction safety and feasibility, structural stress deformation, water resistance, moisture resistance, anti-floating stability and the like of the ultra-deep underground storage structure are solved. The primary lining of the upper structure is an open caisson; the primary lining of the lower structure is mainly composed of a vertical grouting steel pipe, a pre-stressed anchor cable, an occlusion waist beam system and a primary lining concrete layer; the upper end of the vertical grouting steel pipe extends into the blade foot gap, a cement layer is poured into the blade foot gap, and the cement layer and the reinforcing layer are connected into a whole; a concrete lining of the upper structure is fixed to the inner wall of the open caisson, and a waterproof layer is laid between the inner wall of the open caisson and the concrete lining. The concrete lining of the lower structure is fixed on the primary lining concrete layer, and a waterproof layer is laid between the primary lining concrete layer and the concrete lining; the upper end of the fore shaft ring beam is connected with the concrete lining of the upper structure, and the lower end is connected with the concrete lining of the lower structure; and a waterproof layer is laid between the open caisson and the locking mouth ring beam.

Description

Technical Field

[0001] The invention relates to an ultra-deep underground storage structure and a construction method thereof. Background Art

[0002] The ultra-deep underground storage structure has the characteristics of small floor space and large depth. There are currently two methods for its construction: one is to support the foundation pit first, and then construct the storage structure after excavation. However, as the excavation depth increases, the risk of the foundation pit increases significantly. In order to ensure safety, it is necessary to strengthen the support strength, which increases the project cost and construction period; the other method is to sink the main structure into the ground in the form of a caisson. The caisson serves as both the foundation pit support system and the main force system. However, as the sinking depth increases or in hard rock formations, the friction resistance on the outside of the caisson is large and it is difficult to sink. At the same time, a waterproof layer cannot be constructed on the periphery of the caisson, and the waterproof performance of the structure is poor. In addition, the construction of ultra-deep underground storage structures is also plagued by the problem of anti-floating, and the current common practice is to solve it only through counterweights. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a reasonably designed ultra-deep underground storage structure and a construction method thereof.

[0004] The technical solution adopted by the present invention to solve the above-mentioned problems is: an ultra-deep underground storage structure, the storage structure is divided into an upper structure and a lower structure; it is characterized in that: the upper structure is located in the soil layer, the primary lining of the upper structure is a caisson, and a blade foot structure is arranged at the lower end of the caisson, the blade foot structure includes an inner blade foot and an outer blade foot, the inner blade foot and the outer blade foot are both fixedly arranged at the lower end of the caisson, the inner blade foot and the outer blade foot are arranged inside and outside, and a blade foot gap is arranged between the inner blade foot and the outer blade foot; the lower structure is located in the rock layer, and the primary lining of the lower structure is mainly composed of vertical grouting steel pipes, prestressed anchor cables, an interlocking waist beam system and an initial lining concrete layer; the vertical grouting steel pipes are grouted into the rock cracks around them to form a reinforcement layer; the upper end of the vertical grouting steel pipe extends into the blade foot gap, the blade foot gap is poured with a cement layer, and the cement layer is connected to the reinforcement layer as a whole; the interlocking waist beam system includes Steel lattice waist beam, anchor block and anchor rod; the anchor block is arranged in the reinforcement layer, and the steel beam is pre-embedded in the anchor block; the steel lattice waist beam is arranged in the reinforcement layer, and the steel lattice waist beam and the steel beam are spliced ​​into a whole; the anchor rod and the prestressed anchor cable are fixed in the anchor block; the primary lining concrete layer is fixed on the inner wall of the reinforcement layer, and the primary lining concrete layer is fixed to the anchor block; the secondary lining of the upper structure and the lower structure are both concrete lined; the concrete lining of the upper structure is fixed on the inner wall of the caisson, and a waterproof layer is laid between the inner wall of the caisson and the concrete lining; the concrete lining of the lower structure is fixed on the primary lining concrete layer, and a waterproof layer is laid between the primary lining concrete layer and the concrete lining; a locking ring beam is arranged on the lower end of the caisson, the upper end of the locking ring beam is connected to the concrete lining of the upper structure, and the lower end is connected to the concrete lining of the lower structure; a waterproof layer is laid between the caisson and the locking ring beam.

[0005] The blade foot structure of the present invention also includes a blade foot platform, which is fixedly arranged at the lower end of the caisson, and the inner blade foot is fixed on the blade foot platform; a hole is arranged on the blade foot platform, and the hole is connected to the blade foot gap.

[0006] The invention pre-buries steel bar connection sleeves in the upper and lower ends of the locking ring beam, the steel bar connection sleeve at the upper end of the locking ring beam is connected to the pre-buried steel bars in the upper structure concrete lining, and the steel bar connection sleeve at the lower end of the locking ring beam is connected to the pre-buried steel bars in the lower structure concrete lining.

[0007] The anchor block of the present invention has a square plane and a trapezoidal side surface.

[0008] A shear-resistant block protruding toward the inside of the rock mass is arranged at the middle and upper part of the soil-facing side of the anchor block of the present invention.

[0009] The anchor block of the present invention is provided with an anchor cable channel and an anchor sealing groove on its back soil side; the prestressed anchor cable and anchor rod pass through the anchor cable channel, and after the anchor is sealed in the anchor sealing groove, the anchor sealing groove is filled with a cement layer.

[0010] The inner wall of the caisson of the present invention is evenly provided with reserved grooves, and the top is provided with a protruding crown beam.

[0011] The anchor rod of the present invention is arranged obliquely upward, and the prestressed anchor cable is arranged obliquely downward.

[0012] A method for constructing an ultra-deep underground storage structure, characterized in that it comprises the following steps: 1) First, construct the vertical grouting steel pipe to the predetermined elevation, and then inject grout into the rock cracks around it through the vertical grouting steel pipe to form a reinforcement layer to strengthen the stratum; 2) The caisson is sunk in sections until it reaches the designed depth. After the lowest section of the caisson is in place, the upper end of the vertical grouting steel pipe is inserted into the gap between the blade feet; 3) Inject cement slurry into the gap between the blade feet to form a cement layer, which is connected to the reinforcement layer to seal the caisson and the rock mass reinforced by the vertical grouting steel pipe; 4) Lay a waterproof layer at the location where the locking ring beam is set at the lower end of the caisson, and then construct the locking ring beam; 5) After the construction of the locking ring beam is completed, the lower structure is constructed in sections. After each section of the rock mass is excavated, the vertical prestressed anchor cable and the interlocking waist beam system are immediately constructed, and then concrete is sprayed on the inner wall of the reinforcement layer to form the primary lining concrete layer; 6) After the primary lining construction of each lower structure is completed, the waterproof layer is laid immediately, and the surrounding rock pressure and deformation are monitored in real time. According to the monitoring data, the secondary lining structure within the excavation range of this section is constructed in a timely manner using the reverse method; 7) Repeat steps 5)-6) until the construction reaches the designed elevation, and pour the bottom cushion layer in time; 8) During the implementation of the lower structure, the waterproof layer and secondary lining structure of the upper caisson are constructed at the same time. The secondary lining of the upper structure should be connected as a whole with the locking ring beam at the bottom.

[0013] After step 8), the present invention further comprises step 9): constructing equipment rooms and internal partition layers inside the storage structure.

[0014] Compared with the prior art, the present invention has the following advantages and effects: 1. The structure adopts a three-layer waterproof system: the first layer consists of the upper and lower primary linings, and is sealed as a whole by pouring a cement layer into the gap between the two layers of blade feet; the second layer consists of the secondary lining and the waterproof layer laid between the two linings; the third layer consists of the upper and lower secondary linings, and is connected as a whole by a locking ring beam; 2. The anti-floating system of the structure consists of three parts: the deadweight of the primary and secondary lining structures, the tensile strength provided by the prestressed anchor cables, and the frictional resistance between the primary lining and the stratum. Among them, the caisson and the interlocking waist beam system can fully interlock with the secondary lining structure to effectively transmit the vertical force. When the groundwater head acts on the structure, the remaining buoyancy after deducting its deadweight: one part is transmitted to the prestressed anchor cables through the interlocking waist beam system, and then transmitted to the deep rock formation; the other part is transmitted to the caisson wall through the interlocking action of the secondary lining and the caisson, and finally shared by the frictional resistance between the well wall and the stratum.

[0015] 3. The present invention adopts different lining types according to the different properties of the strata within the depth range of the ultra-deep structure, and invents a series of detailed node methods, which effectively connects the upper and lower types of structures into a whole, and systematically solves a series of problems such as the safety and feasibility of ultra-deep underground storage structure construction, structural deformation under stress, waterproof and moisture-proof, anti-floating stability, etc. The present invention is particularly suitable for the situation where bedrock exists below a certain burial depth range of the ultra-deep storage structure. The invention has a sufficient theoretical basis, is conducive to mechanized construction, is safe and economical, and is not limited to the field of industrial or civil underground storage, and has a high value for promotion and application in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the cross-sectional structure of an embodiment of the present invention.

[0017] Figure 2 for Figure 1 Schematic diagram of the enlarged structure at point A in the middle.

[0018] Figure 3 It is a schematic diagram of the planar structure of the lower end of the caisson according to an embodiment of the present invention.

[0019] Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure of BB.

[0020] Figure 5 It is a schematic structural diagram of the locking ring beam according to an embodiment of the present invention.

[0021] Figure 6 for Figure 1 Schematic diagram of the enlarged structure at point C in the middle.

[0022] Figure 7 It is a schematic diagram of a partial plan cross-sectional structure of the lower structure of an embodiment of the present invention.

[0023] Figure 8 It is a schematic side view of the structure of the interlocking waist beam system according to an embodiment of the present invention.

[0024] Figure 9-1 and Figure 9-2 All of them are schematic diagrams of the force transmission path of the anchor block in embodiments of the present invention.

[0025] Fig.10 It is a construction process diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and by way of examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0027] The storage structure of the embodiment of the present invention is divided into an upper structure and a lower structure, and the overall construction method of primary lining + waterproof layer + secondary lining is adopted, but different lining types are adopted according to the different geology of the upper and lower parts.

[0028] The upper structure is located in the soil layer, and the primary lining of the upper structure is the caisson 1. The caisson 1 is easy to sink in the soil and avoids the risk of large deformation of the soil foundation pit. The lower end of the caisson 1 is provided with a blade foot structure, which includes an inner blade foot 41, an outer blade foot 42 and a blade foot platform 43. The outer blade foot 42 and the blade foot platform 43 are both fixedly arranged at the lower end of the caisson 1, and the inner blade foot 41 is fixed on the blade foot platform 43. In this way, the inner blade foot 41 is arranged at the lower end of the caisson 1, and the inner blade foot 41 and the outer blade foot 42 are arranged inside and outside, and a blade foot gap is arranged between the inner blade foot 41 and the outer blade foot 42. A hole 5 is arranged on the blade foot platform 43, and the hole 5 is connected to the blade foot gap, which can be used as an excavation port and a grouting port during construction.

[0029] The lower structure is located in the rock formation. Due to the strong self-stabilizing ability of the rock formation, the primary lining of the lower structure is mainly composed of vertical grouting steel pipes 6, prestressed anchor cables 10, interlocking waist beam systems 11 and primary lining concrete layers 12. The vertical grouting steel pipe 6 is grouted into the rock cracks around it to form a reinforcement layer 22; the upper end of the vertical grouting steel pipe 6 extends into the gap between the blade feet. The gap between the blade feet is poured with a cement layer 7, and the cement layer 7 is connected to the reinforcement layer 22 as a whole. It has three functions: first, it closes the gap between the upper and lower primary linings, so that the closed primary lining serves as the first water-stopping system; second, it hardens the soil between the vertical grouting steel pipe 6 and the blade foot, which can transmit horizontal reaction force and support the vertical grouting steel pipe 6; third, it serves as an internal cross brace of the well wall, enhancing the stability of the structure.

[0030] The interlocking waist beam system 11 can interlock the secondary lining and primary lining of the lower structure, effectively transfer vertical force, and thus ensure that the whole structure can bear force together and work in coordination. The interlocking waist beam system 11 includes a steel lattice waist beam 14, an anchor block 15 and an anchor rod 16. The anchor block 15 is arranged in the reinforcement layer 22, and a steel beam 17 is pre-embedded in the anchor block 15, and the steel beam 17 extends out of the anchor block 15 for a certain length. The steel lattice waist beam 14 is arranged in the reinforcement layer 22, and the steel lattice waist beam 14 and the steel beam 17 are spliced ​​into a whole.

[0031] The anchor rod 16 and the prestressed anchor cable 10 are both fixed in the anchor block 15. The anchor rod 16 is set obliquely upward, and the prestressed anchor cable 10 is set obliquely downward. The plane of the anchor block 15 is square and the side is trapezoidal. The shear-resistant block 18 protruding toward the inside of the rock mass is set in the middle and upper part of the soil-facing side, which can keep it stable in the vertical direction; the anchor block 15 is reserved with an anchor cable channel, and a sealing anchor groove 19 is reserved on the soil-receiving side. After the prestressed anchor cable 10 and the anchor rod 16 pass through the anchor cable channel and are anchored in the sealing anchor groove 19, the sealing anchor groove 19 is filled with a cement layer; the thickness of the anchor block 15 is greater than the thickness of the primary lining concrete layer 12, so that after the primary lining concrete layer 12 and the waterproof layer 13 are laid, the anchor block 15 can still penetrate into the secondary lining and bite with it, thereby transmitting the vertical force. The primary lining concrete layer 12 is fixed on the inner wall of the reinforcement layer 22, and the primary lining concrete layer 12 is fixed to the anchor block 15.

[0032] The secondary linings of both the upper structure and the lower structure are made of concrete lining 2 formed by cast-in-place concrete, and different construction procedures are adopted according to the stiffness of the primary lining and the different strata: the secondary lining of the upper structure is constructed by the forward method, while the secondary lining of the lower structure is constructed by the reverse method in a timely manner by real-time monitoring of the deformation of the surrounding rock. The concrete lining 2 of the upper structure is fixed on the inner wall of the caisson 1; reserved grooves 20 are evenly opened on the inner wall of the caisson 1, and a protruding crown beam 21 is provided on the top, so that the connection between the caisson 1 and the concrete lining 2 is more secure; a waterproof layer 13 is laid between the inner wall of the caisson 1 and the concrete lining 2; the reserved groove 20 is trapezoidal, which ensures full engagement with the secondary lining concrete while also allowing the waterproof layer 13 to fit closely with it. The concrete lining 2 of the lower structure is fixed on the primary lining concrete layer 12, and a waterproof layer 13 is laid between the primary lining concrete layer 12 and the concrete lining 2.

[0033] The specific transmission path of anchor block 15 is shown in Figure 9-1 and Figure 9-2 : During construction, the weight transfer of the secondary lining is F G to the upper surface of the anchor block 15, F G The tension F1 provided by the anchor rod 16, the vertical shear force V1 of the shear block 18 and the supporting force F2 provided by the rock mass below the anchor block 15 are jointly borne; during the normal service life, the upward water buoyancy F N The force is transmitted to the lower surface of the anchor block 15 and is borne by the tension F3 in the direction of the prestressed anchor cable 10 , the vertical shear force V2 on the shear block 18 , and the supporting force F4 provided by the rock mass above the anchor block 15 .

[0034] A locking ring beam 8 is arranged at the lower end of the caisson 1. The upper end of the locking ring beam 8 is connected to the concrete lining 2 of the upper structure, and the lower end is connected to the concrete lining 2 of the lower structure. Steel bar connecting sleeves 9 are embedded in the upper and lower ends of the locking ring beam 8. The steel bar connecting sleeve 9 at the upper end of the locking ring beam 8 is connected to the embedded steel bars in the concrete lining 2 of the upper structure, and the steel bar connecting sleeve 9 at the lower end of the locking ring beam 8 is connected to the embedded steel bars in the concrete lining 2 of the lower structure. A waterproof layer 13 is laid between the caisson 1 and the locking ring beam 8. The locking ring beam 8 has three functions: first, it bears part of the deadweight when the secondary lining of the lower structure is constructed in a reverse manner; second, it connects the secondary linings of the upper structure and the lower structure as a whole to bear the force together and effectively transmit the vertical force; third, it forms a closed system with the secondary lining as a third waterproof system.

[0035] The cross-sectional shape of the storage structure is not limited to circular or rectangular. The vertical section is wide at the top and narrow at the bottom. The equipment and auxiliary rooms can be arranged within the width of the upper structure. The rest of the internal space is connected from top to bottom, which is more conducive to mechanized layout. The specific division is determined according to the specific function of the storage structure.

[0036] as follows Fig.10 As shown, a method for constructing an ultra-deep underground storage structure comprises the following steps: 1) First, construct the vertical grouting steel pipe 6 pile to a predetermined elevation, and then inject grout into the rock mass cracks around the vertical grouting steel pipe 6 to form a reinforcement layer 22 to reinforce the stratum; 2) The caisson 1 is sunk in sections until it reaches the designed depth. After the lowest section of the caisson 1 is in place, the upper end of the vertical grouting steel pipe 6 is extended into the gap between the blade feet; 3) Cement slurry is injected into the gap between the blade feet through the hole 5 to form a cement layer 7, which is connected to the reinforcement layer 22 as a whole, so that the caisson 1 and the rock mass reinforced by the vertical grouting steel pipe 6 are sealed, and the external groundwater is completely isolated from the interior of the structure, which serves as the first waterproof system; 4) A waterproof layer 13 is laid at the position where the locking ring beam 8 is set at the lower end of the caisson 1, and then the locking ring beam 8 is constructed to prepare for the subsequent construction of the lower structure using the reverse construction method; 5) After the construction of the locking ring beam 8 is completed, the lower structure is constructed in sections. After each section of the rock mass is excavated, the vertical prestressed anchor cable 10 and the interlocking waist beam system 11 are immediately constructed, and then concrete is sprayed on the inner wall of the reinforcement layer 22 to form the primary lining concrete layer 12; 6) After the primary lining construction of each lower structure is completed, the waterproof layer 13 is laid immediately, and the surrounding rock pressure and deformation are monitored in real time. According to the monitoring data, the secondary lining structure within the excavation range of this section is constructed in a timely manner using the reverse method; 7) Repeat steps 5)-6) until the construction reaches the designed elevation, and pour the bottom cushion in time; then lay the waterproof layer 13 of the structural bottom plate, and construct the structural bottom plate; 8) During the construction of the lower structure, the waterproof layer 13 and the secondary lining structure of the upper caisson 1 are constructed simultaneously. The secondary lining of the upper structure should be connected as a whole with the locking ring beam 8 at the bottom; 9) Construct the equipment room and internal partition layer inside the storage structure. At this time, the main part of the ultra-deep underground storage structure is completed. While ensuring the safety and stability of the structure, it can effectively prevent seepage, water and floating.

[0037] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the present invention. All equivalent changes or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. Technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. An ultra-deep underground storage structure, the storage structure is divided into an upper structure and a lower structure; characterized in that: The upper structure is located in the soil layer, and the primary lining of the upper structure is a caisson. A blade foot structure is arranged at the lower end of the caisson, and the blade foot structure includes an inner blade foot and an outer blade foot. The inner blade foot and the outer blade foot are fixedly arranged at the lower end of the caisson, and the inner blade foot and the outer blade foot are arranged inside and outside, and a blade foot gap is arranged between the inner blade foot and the outer blade foot; the lower structure is located in the rock layer, and the primary lining of the lower structure is mainly composed of vertical grouting steel pipes, prestressed anchor cables, an interlocking waist beam system and an initial lining concrete layer; the vertical grouting steel pipes are grouted into the rock cracks around them to form a reinforcement layer; the upper end of the vertical grouting steel pipe extends into the blade foot gap, and a cement layer is poured into the blade foot gap, and the cement layer is connected to the reinforcement layer as a whole; the interlocking waist beam system includes a steel lattice waist beam, an anchor block and an anchor rod; the anchor block is arranged in the reinforcement layer, and the anchor block Steel beams are embedded in the middle; steel lattice waist beams are arranged in the reinforcement layer, and the steel lattice waist beams are spliced ​​with the steel beams into a whole; anchor rods and prestressed anchor cables are fixed in the anchor blocks; a primary lining concrete layer is fixed on the inner wall of the reinforcement layer, and the primary lining concrete layer is fixed to the anchor blocks; the secondary linings of the upper structure and the lower structure are both concrete lined; the concrete lining of the upper structure is fixed on the inner wall of the caisson, and a waterproof layer is laid between the inner wall of the caisson and the concrete lining; the concrete lining of the lower structure is fixed on the primary lining concrete layer, and a waterproof layer is laid between the primary lining concrete layer and the concrete lining; a locking ring beam is arranged on the lower end of the caisson, the upper end of the locking ring beam is connected to the concrete lining of the upper structure, and the lower end is connected to the concrete lining of the lower structure; a waterproof layer is laid between the caisson and the locking ring beam.

2. The ultra-deep underground storage structure according to claim 1, characterized in that: The blade foot structure also includes a blade foot platform, which is fixedly arranged at the lower end of the caisson, and the inner blade foot is fixed on the blade foot platform; a hole is arranged on the blade foot platform, and the hole is connected with the blade foot gap.

3. The ultra-deep underground storage structure according to claim 1, characterized in that: Rebar connecting sleeves are embedded in the upper and lower ends of the locking ring beam. The rebar connecting sleeve at the upper end of the locking ring beam is connected to the embedded rebar in the upper structure concrete lining, and the rebar connecting sleeve at the lower end of the locking ring beam is connected to the embedded rebar in the lower structure concrete lining.

4. The ultra-deep underground storage structure according to claim 1, characterized in that: The anchor block has a square plane and a trapezoidal side surface.

5. The ultra-deep underground storage structure according to claim 1, characterized in that: A shear-resistant block protruding toward the inside of the rock mass is arranged at the middle and upper part of the soil-facing side of the anchor block.

6. The ultra-deep underground storage structure according to claim 1, characterized in that: An anchor cable channel is reserved in the anchor block, and an anchor sealing groove is reserved on the soil-backed side thereof; the prestressed anchor cable and anchor rod pass through the anchor cable channel, and after the anchor is sealed in the anchor sealing groove, the anchor sealing groove is filled with a cement layer.

7. The ultra-deep underground storage structure according to claim 1 is characterized in that: The inner wall of the caisson is evenly provided with reserved grooves, and the top is provided with a protruding crown beam.

8. The ultra-deep underground storage structure according to claim 1, characterized in that: The anchor rod is arranged obliquely upward, and the prestressed anchor cable is arranged obliquely downward.

9. A method for constructing an ultra-deep underground storage structure according to any one of claims 1 to 8, characterized in that: The steps include: 1) First, construct the vertical grouting steel pipe to the predetermined elevation, and then inject grout into the rock cracks around it through the vertical grouting steel pipe to form a reinforcement layer to strengthen the stratum; 2) The caisson is sunk in sections until it reaches the designed depth. After the lowest section of the caisson is in place, the upper end of the vertical grouting steel pipe is inserted into the gap between the blade feet; 3) Inject cement slurry into the gap between the blade feet to form a cement layer, which is connected to the reinforcement layer to seal the caisson and the rock mass reinforced by the vertical grouting steel pipe; 4) Lay a waterproof layer at the location where the locking ring beam is set at the lower end of the caisson, and then construct the locking ring beam; 5) After the construction of the locking ring beam is completed, the lower structure is constructed in sections. After each section of the rock mass is excavated, the vertical prestressed anchor cable and the interlocking waist beam system are immediately constructed, and then concrete is sprayed on the inner wall of the reinforcement layer to form the primary lining concrete layer; 6) After the primary lining construction of each lower structure is completed, the waterproof layer is laid immediately, and the surrounding rock pressure and deformation are monitored in real time. According to the monitoring data, the secondary lining structure within the excavation range of this section is constructed in a timely manner using the reverse method; 7) Repeat steps 5)-6) until the construction reaches the designed elevation, and pour the bottom cushion layer in time; 8) During the implementation of the lower structure, the waterproof layer and secondary lining structure of the upper caisson are constructed at the same time. The secondary lining of the upper structure should be connected as a whole with the locking ring beam at the bottom.

10. The construction method according to claim 9, characterized in that: After step 8), the method further includes step 9): constructing equipment rooms and internal partition layers inside the storage structure.

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