An insert joint structure for a hybrid dam

Abstract

The application relates to the technical field of hydraulic engineering, in particular to an insertion joint structure for a mixed dam. The insertion joint structure comprises a connecting section for connecting a face dam and a gravity dam; the connecting section is integrally formed with the face dam, one end of the connecting section is provided with an insertion slot for the gravity dam; and a water stop assembly is further arranged in the connecting section. In the insertion joint structure for the mixed dam, the movement of a flexible water stop block is controlled by flowable fillings, when water seeps, the flowable fillings originally blocking the flexible water stop block are washed away by the impact force of water flow, and the flexible water stop block is pushed to move to the end of the gravity dam by the water pressure on the upstream side, so that temporary water stopping at the connecting position of the gravity dam and the connecting section is realized, the workload of repair work is reduced, and the water stopping efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering technology, and more specifically, to an insert joint structure for hybrid dams. Background Technology

[0002] Hybrid dams are a type of dam that combines gravity dams and panel dams. They are widely used because they combine the advantages of both concrete dams and panel dams and are relatively economical. Panel dams are connected to concrete dams, and can generally be constructed using wing-wall or insert-type structures.

[0003] The specific structure of this type is as follows: a variable cross-section concrete dam is inserted into a panel dam for a certain distance, and the panel dam is used to wrap the concrete dam with a smaller cross-section. At the joint, the upstream and downstream slopes of the panel dam remain unchanged, and a 90° cone is used to wrap the partially inserted concrete section (this part of the panel dam is referred to as the "wrap-up"). However, due to the different stiffness of the two dam types, the joint of the hybrid dam results in large differences in deformation and uneven stress distribution. During an earthquake, different seismic responses will occur, making it prone to relative settlement and tension cracks. This is the weakest point of the dam body and a key part of the hybrid dam design.

[0004] When cracks appear at the joint of a composite dam, water from upstream can seep into the downstream area through these cracks, leading to soil erosion within the dam over time. Therefore, waterproofing repair is necessary.

[0005] In traditional repair processes, because the repair work takes a long time, to prevent excessive soil loss inside the dam, it is necessary to first stop the seepage in the seepage area. After the seepage is temporarily stopped, the repair work can proceed. However, traditional methods of stopping the seepage require manual labor, which not only increases the workload of the repair work but also makes it difficult to quickly stop the seepage in the first place. Summary of the Invention

[0006] The purpose of this invention is to provide an insert joint structure for hybrid dams to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, an insert-type joint structure for a hybrid dam is provided, comprising a connecting section for connecting a panel dam and a gravity dam; the connecting section is integrally formed with the panel dam, and one end of the connecting section has a slot for the gravity dam to be inserted; a water-stopping component is also provided inside the connecting section, the water-stopping component comprising at least:

[0008] A movable water-stopping mechanism that moves towards the gravity dam using water pressure from the upstream side;

[0009] Drainable filler is located on the movement path of the movable water-stopping mechanism to restrict the movement of the movable water-stopping mechanism;

[0010] and a flow guide mechanism for guiding water flow to the erodible filler when water seeps;

[0011] When water seeps between the gravity dam and the connecting section, the flow guide mechanism causes water flow to scour the erodible filler, which is then separated from the moving path of the movable water stop mechanism, so that the movable water stop mechanism uses the water pressure on the upstream side to stop water at the connecting part of the connecting section and the gravity dam.

[0012] As a further improvement of the technical solution, the water stop assembly comprises an outer shell arranged in a longitudinal manner inside the connecting section, and the movable water stop mechanism is movably arranged in the outer shell;

[0013] The top of the outer shell is open, the bottom is closed, and the side of the outer shell facing the gravity dam is provided with an opening for the movable water stop mechanism to contact the end surface of the gravity dam.

[0014] As a further improvement of the technical solution, the outer shell has a "convex" structure with a narrow opening side and a wide other side.

[0015] As a further improvement of the technical solution, the movable water stop mechanism comprises a piston block arranged inside the outer shell, the side wall of one end of the piston block close to the opening is attached to the side wall of the opening, and the side wall of the other end close to the panel dam is attached to the inner wall of the outer shell, so that the piston block separates the inside of the outer shell into a water storage cavity and a restriction cavity;

[0016] The water storage cavity is close to the flow guide pipe, and the restriction cavity is close to the opening;

[0017] The end of the piston block facing the gravity dam is fixedly provided with a flexible water stop block;

[0018] The erodible filler is filled in the restriction cavity in a compacted manner.

[0019] As a further improvement of the technical solution, the outer shell is communicated with a flow guide pipe on the side facing the panel dam and a drainage pipe on the side facing the downstream side;

[0020] One end of the flow guide pipe is communicated with the water storage cavity, and the other end penetrates the upstream side of the connecting section to guide the water on the upstream side into the inside of the outer shell to exert a pushing force on the piston block;

[0021] One end of the drainage pipe is communicated with the restriction cavity, and the other end penetrates the downstream side of the connecting section to discharge the erodible filler in the inside of the outer shell when water seeps.

[0022] As a further improvement of the technical solution, the side wall of the opening close to the upstream side has a thick end and a thin end;

[0023] The thin end of the opening is arranged close to the restriction cavity;

[0024] The flow guide mechanism is a water inlet channel formed between the thinner end of the opening and the side wall of the piston block.

[0025] As a further improvement of the technical solution, the side wall of the convex end of the piston block is provided with a through drainage channel.

[0026] As a further improvement of the technical solution, one end of the drainage pipe is in a closed state, and a plurality of openings are arranged at the closed end.

[0027] As a further improvement of the technical solution, the flow guide mechanism includes a shunt pipe having one end in communication with the flow guide pipe and the other end penetrating the shell and being in communication with the limiting cavity; a sealing block is fixedly arranged at the penetrating position of the shunt pipe on the inner wall of the shell, and the bottom of the sealing block is in communication with a pressure applying rod, one end of the pressure applying rod slidingly penetrating the shell and extending to the bottom of the gravity dam.

[0028] When the gravity dam subsides, the gravity dam applies force to the sealing block through the pressure applying rod, so that the connection part of the sealing block and the shell is damaged, and then the water in the shunt pipe flows into the limiting cavity.

[0029] As a further improvement of the technical solution, the connection strength between the pressure applying rod and the sealing block is greater than the connection strength between the sealing block and the shell.

[0030] Compared with the prior art, the beneficial effects of the present application are:

[0031] 1. In the plug-in joint structure for the mixed dam, the movement of the flexible water stop block is controlled by the flowable filling material, and when water seeps, the flowable filling material that originally blocks the flexible water stop block is washed away by the impact force of the water flow, and the flexible water stop block is pushed to move towards the end of the gravity dam by the water pressure on the upstream side, thereby realizing temporary water stop at the connection between the gravity dam and the connecting section. Not only reduces the workload of repair work, but also improves the efficiency of water stop.

[0032] 2. In the plug-in joint structure for the mixed dam, due to the arrangement of the flowable filling material, the flexible water stop block is not tightly attached to the gravity dam in normal state, and is tightly attached to the gravity dam only when water seeps, thereby prolonging the service life of the flexible water stop block. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a schematic diagram of the overall structure of the present application;

[0034] Figure 2 is a schematic diagram of the structure of the connecting section of the present application;

[0035] Figure 3Structure diagram of water stop mechanism of the present application;

[0036] Figure 4 Structure diagram of flowable material of the present application;

[0037] Figure 5 Structure diagram of drainage passage of the present application;

[0038] Figure 6 Structure diagram of drainage pipe of the present application;

[0039] Figure 7 Structure diagram of connecting section of the present application;

[0040] Figure 8 Structure diagram of A of the present application Figure 7

[0041] Figure 9 Structure diagram of flow distribution pipe of the present application;

[0042] Figure 10 Structure diagram of sealing block of the present application;

[0043] Figure 11 Structure diagram of pressure applying rod of the present application.

[0044] The meanings of the respective reference numerals in the drawings are as follows:

[0045] 100, face slab; 101, upstream side; 102, downstream side; 110, gravity dam; 200, connecting section; 201, reinforced concrete face slab; 202, toe slab; 203, insertion slot; 210, water stop assembly; 211, outer shell; 212, opening; 213, flow guide pipe; 214, drainage pipe; 215, water storage cavity; 216, limiting cavity; 217, water inlet passage; 218, flowable filler; 220, piston block; 221, flexible water stop block; 222, drainage passage; 230, flow distribution pipe; 231, sealing block; 232, pressure applying rod. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0047] ​In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0048] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly specified.

[0049] The panel dam 100, also known as an earth dam, can be formed by stacking local materials such as soil, gravel, etc., and has a trapezoidal shape with a narrow upper part and a wide lower part. The toe plate 202 is based on the strongly weathered layer of bedrock. The upstream side 101 for retaining water uses a reinforced concrete panel 201 structure to prevent water from seeping into the interior of the panel dam 100. The gravity dam 110 is formed by pouring concrete material, and one end is inserted into the interior of the panel dam 100 to form a hybrid dam together with the panel dam 100.

[0050] The joint part of the hybrid dam has a large difference in deformation and uneven stress distribution due to the different stiffness of the two dam types, resulting in different seismic responses during an earthquake, and is prone to relative settlement and tensile cracks, causing water leakage at the connection between the panel dam 100 and the gravity dam 110.

[0051] Therefore, the present application provides an insertion joint structure for a hybrid dam, as shown in Figure 1 The connection section 200 is integrally formed with the panel dam 100 and is stacked on both sides of the upstream side 101 and the downstream side 102. The slope of the connection section 200 is the same as that of the panel dam 100. The upstream side 101 of the connection section 200 is also poured with a reinforced concrete panel 201 to prevent water from seeping into the interior of the connection section 200.

[0052] As shown in Figure 2As shown, during the construction of the connecting section 200, a support is built at one end of the connecting section 200 near the panel dam 100 to support the fill material (e.g., soil, gravel). After the connecting section 200 is completed, the support at one end of the connecting section 200 is removed. At this time, a slot 203 is formed at one end of the connecting section 200. The shape of the slot 203 corresponds to the end of the gravity dam 110 so that the panel dam 100 can be inserted to achieve the connection between the gravity dam 110 and the connecting section 200.

[0053] In addition, the end of the connecting section 200 near the gravity dam 110 is a 90° conical structure (reference). Figure 2 The shape of the end of the connecting section 200 is adjusted to reduce the principal stress of the connecting section 200.

[0054] It should be understood that the support is, for example, a template. By combining multiple templates into a shape corresponding to the gravity dam 110, the template corresponding to the shape of the gravity dam 110 can support the stacked fill material during the stacking of the connecting section 200, thereby obtaining the slot 203 after filling.

[0055] The connecting section 200 is also equipped with a water-stopping component 210, which includes a movable water-stopping mechanism, a flow guiding mechanism, and a washable filler 218 (such as soil, gravel, etc.). The movable water-stopping mechanism moves towards the gravity dam 110 using the water pressure on the upstream side 101. The washable filler 218 is located on the movement path of the movable water-stopping mechanism and is used to restrict the movement of the movable water-stopping mechanism. When seepage occurs between the gravity dam 110 and the connecting section 200, the flow guiding mechanism directs the water towards the washable filler 218, forcing the washable filler 218 to be flushed by the water and removed from the movement path of the movable water-stopping mechanism. This allows the movable water-stopping mechanism to use the water pressure on the upstream side 101 to stop the water flow at the connection between the connecting section 200 and the gravity dam 110.

[0056] like Figure 3 As shown, the water-stopping component 210 includes a housing 211 embedded longitudinally inside the connecting section 200, the housing 211 preferably being made of steel plate. A movable water-stopping mechanism is movably disposed within the housing 211. When installing the housing 211, a groove is first pre-reserved at the top of the connecting section 200 during the filling process, one side of the groove communicating with the slot 203, and then the housing 211 is placed into the groove.

[0057] The top of the outer casing 211 is open (to facilitate the subsequent addition of drainable filler 218, which can be sealed later with a cover plate), while the bottom is closed. An opening 212 is provided on the side of the outer casing 211 facing the gravity dam 110, allowing the movable water-stopping mechanism to contact the end face of the gravity dam 110.

[0058] like Figure 4As shown, the shell 211 is in a "convex" shape structure with the opening 212 side narrow and the other side wide.

[0059] The movable water-stopping mechanism comprises a piston block 220 arranged inside the shell 211, the piston block 220 is attached to the side wall of the opening 212 near one end and attached to the inner wall of the shell 211 near the side wall of the end of the panel dam 100. In this way, the piston block 220 divides the inside of the shell 211 into two spaces, one is the water storage cavity 215 (near the flow guide pipe 213), and the other is the restriction cavity 216 (near the opening 212). The end of the piston block 220 towards the gravity dam 110 is fixedly provided with a flexible water-stopping block 221, which is preferably made of rubber material. The rubber material is soft, which can improve the sealing between the flexible water-stopping block 221 and the end face of the gravity dam 110, and the width of the flexible water-stopping block 221 is less than the width of the opening 212 to allow water flow to enter. At the same time, the flowable filler 218 is filled in the restriction cavity 216, and the filling is carried out in a compacted manner. Compaction can prevent the flowable filler 218 from flowing under natural conditions (non-seepage conditions).

[0060] That is, the movement of the flexible water-stopping block 221 is controlled by the filled flowable filler 218. When seepage occurs, the flowable filler 218 that originally blocks the flexible water-stopping block 221 is washed out by the impact force of the water flow, and the flexible water-stopping block 221 is pushed by the water pressure on the upstream side 101 to move towards the end of the gravity dam 110, thereby achieving temporary water-stopping at the connection between the gravity dam 110 and the connecting section 200. Not only does this reduce the workload of repair work, but it also improves the efficiency of water-stopping.

[0061] Furthermore, due to the arrangement of the flowable filler 218, the flexible water-stopping block 221 does not tightly adhere to the gravity dam 110 under normal conditions, and only tightly adheres to the gravity dam 110 under seepage conditions, thereby improving the service life of the flexible water-stopping block 221.

[0062] Further, the shell 211 is connected to the flow guide pipe 213 on the side towards the panel dam 100 and the drainage pipe 214 on the side towards the downstream side 102; one end of the flow guide pipe 213 is connected to the water storage cavity 215, and the other end penetrates the upstream side 101 of the connecting section 200 to guide the water on the upstream side 101 into the inside of the shell 211 to apply a pushing force to the piston block 220; one end of the drainage pipe 214 is connected to the restriction cavity 216, and the other end penetrates the downstream side 102 of the connecting section 200 to discharge the flowable filler 218 inside the shell 211 when seepage occurs.

[0063] In some embodiments, the opening 212 is tapered, with the side wall of the upstream side 101 being thicker at one end and thinner at the other end, and the thinner end of the opening 212 is located close to the restriction cavity 216. The flow guide mechanism is the water inlet channel 217 formed between the thinner end of the opening 212 and the side wall of the piston block 220.

[0064] When the water seepage flows into the restriction cavity 216 through the water inlet channel 217, the erodible filler 218 needs to be flushed out so as to be discharged through the drain pipe 214. To this end, as shown in Figure 5 , the side wall of the protruding end of the piston block 220 is provided with a through drain channel 222. When the water flow enters one end of the restriction cavity 216, the water flow can flow to the other end through the drain channel 222, thereby flushing the erodible filler 218 in the restriction cavity 216.

[0065] Moreover, as shown in Figure 6 , one end of the drain pipe 214 is closed, and a plurality of openings are provided at the closed end. By providing a plurality of openings, the discharge efficiency of the drain pipe 214 is reduced, and the erosion speed of the connecting section 200 under natural conditions is reduced.

[0066] Working principle:

[0067] In combination with Figure 7 and Figure 8 , under normal conditions, the water on the upstream side 101 flows into the water storage cavity 215 through the flow guide pipe 213 and exerts a pushing force on the piston block 220 to move towards the gravity dam 110. At the same time, the erodible filler 218 is filled in the restriction cavity 216 to limit the movement of the piston block 220, and the flexible water stop block 221 does not tightly fit the end of the gravity dam 110 at this time.

[0068] When water seepage occurs between the gravity dam 110 and the connecting section 200, as shown in Figure 8 , the water of the gravity dam 110 flows into the water inlet channel 217 through the gap between the gravity dam 110 and the connecting section 200, and then flows into the restriction cavity 216 through the water inlet channel 217, and finally is discharged through the drain pipe 214. During the flow of water in the restriction cavity 216, the water continuously carries away the erodible filler 218 in the restriction cavity 216, so that the amount of the erodible filler 218 is reduced. When the amount of the erodible filler 218 is reduced, the water in the water storage cavity 215 pushes the piston block 220 and the flexible water stop block 221 towards the end of the gravity dam 110, so that the end of the flexible water stop block 221 tightly fits the end of the gravity dam 110. Thus, temporary water stopping of the upstream side 101 is achieved, and at the same time, the side wall of the piston block 220 blocks the water inlet channel 217 after moving, preventing the water flow from continuously discharging through the water inlet channel 217.

[0069] In other embodiments, as shown in Figure 9- Figure 11 The inner wall of the outer shell 211 is fixedly provided with a sealing block 231 at the position where the shunt pipe 230 penetrates, and the bottom of the sealing block 231 is communicated with a pressing rod 232. One end of the pressing rod 232 extends to the bottom of the gravity dam 110 after penetrating the outer shell 211. When the gravity dam 110 subsides, the gravity dam 110 exerts a force on the pressing rod 232 through the pressing rod 232, so that the connection between the pressing rod 232 and the outer shell 211 is damaged, and then the water in the shunt pipe 230 flows into the limiting cavity 216.

[0070] Therefore, under normal circumstances, part of the water in the flow guide pipe 213 enters the shunt pipe 230 and is blocked by the sealing block 231, and at this time the water in the shunt pipe 230 cannot enter the limiting cavity 216. When the gravity dam 110 subsides, the gravity dam 110 subsides and presses the pressing rod 232 to move downward, and the pressing rod 232 moves downward to drive the sealing block 231 to move downward. When the downward force on the pressing rod 232 is greater than the connection strength between the sealing block 231 and the outer shell 211, a crack is generated between the sealing block 231 and the outer shell 211, and at this time the water in the shunt pipe 230 can flow into the limiting cavity 216 to flush the flowable filler 218.

[0071] For example, the sealing block 231 and the outer shell 211 are both made of metal material, and are connected by welding during connection. The connection strength between the pressing rod 232 and the sealing block 231 should be greater than the connection strength between the sealing block 231 and the outer shell 211. In this way, when the gravity dam 110 subsides, the gravity dam 110 can use its own weight to press the sealing block 231 through the pressing rod 232 to separate from the outer shell 211.

[0072] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. An insert joint structure for a hybrid dam, comprising a connecting section (200) for connecting a panel dam (100) and a gravity dam (110); the connecting section (200) is integrally formed with the panel dam (100), and one end of the connecting section (200) has a slot (203) for inserting the gravity dam (110); characterized in that: The connecting section (200) is further provided with a water-stopping component (210), which includes at least: The movable water-stopping mechanism moves towards the gravity dam (110) using the water pressure on the upstream side (101); Drainable filler (218) is located on the movement path of the movable water-stopping mechanism to restrict the movement of the movable water-stopping mechanism; And a flow guiding mechanism for directing the water flow during seepage to the runoff filler (218); When seepage occurs between the gravity dam (110) and the connecting section (200), the flow guiding mechanism causes the water flow to flush the washable filler (218), causing the washable filler (218) to move away from the moving path of the movable water-stopping mechanism, thereby allowing the movable water-stopping mechanism to use the water pressure on the upstream side (101) to stop the water flow at the connection between the connecting section (200) and the gravity dam (110).

2. The insert joint structure for hybrid dams according to claim 1, characterized in that: The water-stopping assembly (210) includes a housing (211) disposed longitudinally inside the connecting section (200), and the movable water-stopping mechanism is movably disposed within the housing (211); The top of the outer shell (211) is open and the bottom is closed. The outer shell (211) has an opening (212) on the side facing the gravity dam (110) so that the movable water-stopping mechanism can contact the end face of the gravity dam (110).

3. The insert joint structure for hybrid dams according to claim 2, characterized in that: The outer shell (211) has a "convex" shaped structure with a narrow opening (212) on one side and a wide opening on the other side.

4. The insert joint structure for hybrid dams according to claim 2, characterized in that: The movable water-stopping mechanism includes a piston block (220) disposed inside the outer shell (211). The side wall of the piston block (220) near the opening (212) is attached to the side wall of the opening (212), and the side wall facing the panel dam (100) is attached to the inner wall of the outer shell (211), so that the piston block (220) divides the interior of the outer shell (211) into a water storage chamber (215) and a confinement chamber (216). The water storage chamber (215) is close to the guide pipe (213), and the confinement chamber (216) is close to the opening (212). A flexible water-stop block (221) is fixedly installed at one end of the piston block (220) facing the gravity dam (110); The drainable filler (218) is compacted and filled into the confined cavity (216).

5. The insert joint structure for a hybrid dam according to claim 4, characterized in that: The outer shell (211) is connected to a flow guide pipe (213) on the side facing the panel dam (100), and to a drainage pipe (214) on the side facing the downstream side (102). One end of the guide pipe (213) is connected to the water storage chamber (215), and the other end passes through the upstream side (101) of the connecting section (200) to guide the water on the upstream side (101) into the shell (211) and apply thrust to the piston block (220); One end of the drain pipe (214) is connected to the confining cavity (216), and the other end passes through the downstream side (102) of the connecting section (200), which is used to discharge the runoff filler (218) inside the shell (211) when water seepage occurs.

6. The insert joint structure for a hybrid dam according to claim 5, characterized in that: The sidewall of the opening (212) near the upstream side (101) is thick at one end and thin at the other end; The thinner end of the opening (212) is positioned close to the limiting cavity (216); The flow guiding mechanism is a water inlet channel (217), which is formed between the thinner end of the opening (212) and the side wall of the piston block (220).

7. The insert joint structure for hybrid dams according to claim 4, characterized in that: The piston block (220) has a through drainage channel (222) on the side wall of the protruding end.

8. The insert joint structure for a hybrid dam according to claim 5, characterized in that: One end of the drain pipe (214) is closed, and multiple openings are provided at the closed end.

9. The insert joint structure for a hybrid dam according to claim 5, characterized in that: The flow guiding mechanism includes a diversion pipe (230) with one end connected to the flow guiding pipe (213) and the other end penetrating the outer shell (211) and connected to the limiting cavity (216); a sealing block (231) is fixedly installed on the inner wall of the outer shell (211) at the penetration point of the diversion pipe (230); a pressure rod (232) is connected to the bottom of the sealing block (231); one end of the pressure rod (232) slides through the outer shell (211) and extends to the bottom of the gravity dam (110); When the gravity dam (110) settles, the gravity dam (110) applies force to the sealing block (231) through the pressure rod (232), so that the connection between the sealing block (231) and the outer shell (211) is destroyed, and the water in the diversion pipe (230) flows into the confinement chamber (216).

10. The insert joint structure for a hybrid dam according to claim 9, characterized in that: The connection strength between the pressure rod (232) and the sealing block (231) is greater than the connection strength between the sealing block (231) and the outer shell (211).

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