Retaining dam and prevention integrated open tunnel structure

Abstract

The application relates to the civil engineering field and discloses a blocking dam and prevention and treatment integrated open tunnel structure. The blocking dam, wherein, the frame type grid dam is arranged on the top and at least one side of the tunnel body; the frame type grid dam extends along the length direction of the tunnel body; the frame type grid dam comprises a retaining wall for blocking impact objects generated by geological disasters, a drainage port arranged on the retaining wall and a grid fixed in the drainage port. The prevention and treatment integrated open tunnel structure comprises a tunnel body, the above blocking dam and a drainage culvert; the drainage culvert is pre-buried in the foundation under the blocking dam and / or the tunnel body; the drainage culvert is provided with a slope for draining the accumulated water in the blocking dam and / or draining the accumulated water and / or flowing water around the tunnel body. The above technical scheme can effectively prevent and treat the impact objects generated by geological disasters, greatly improves the space area of road engineering construction and makes the road traffic facilities have a larger living space.

Description

TECHNICAL FIELD

[0001] The present application relates to the civil engineering field, in particular to a dam and prevention integrated open tunnel structure. BACKGROUND

[0002] Mountain torrents and debris flow have the characteristics of strong burst, great destructive power and difficult to predict, often bring potential safety hazards and disaster losses to road facilities and traffic safety. Debris flow dam is a common prevention engineering measure, which can realize the treatment of water and stone separation in debris flow by intercepting solid materials in debris flow without intercepting debris flow slurry. Open tunnel is a prevention structure when road passes through debris flow impact area and accumulation area, which makes debris flow flow out from the top of the tunnel to ensure the safety of road facilities and traffic safety. The two types of structures have good effects when achieving their respective purposes.

[0003] However, in reality, debris flow treatment engineering and open tunnel structure in road protection engineering are often independent of each other, not only in spatial distribution without clear correlation, but also in function, disaster prevention target, safety to environment, engineering design management and post-maintenance. It may lead to the difficulty of unifying debris flow disaster treatment and road traffic facility protection, and the treatment effect of geological disasters does not reach a better degree. SUMMARY

[0004] The present application provides a dam and prevention integrated open tunnel structure to solve the above technical problems that the treatment of debris flow disaster and the protection of road traffic facilities may be difficult to unify, and the treatment effect of geological disasters does not reach a better degree.

[0005] According to an aspect of the present application, an embodiment provides a dam, comprising:

[0006] A frame type grid dam is arranged at the top and at least one side of the tunnel body, and extends along the length direction of the tunnel body.

[0007] The frame type grid dam comprises:

[0008] A retaining wall extends along the length direction of the tunnel body and is used to block impact materials generated by geological disasters.

[0009] A drainage port is arranged on the retaining wall.

[0010] A grid is fixed in the drainage port and used to intercept large particles in the impact materials.

[0011] In one embodiment, the frame-type grid dam is formed as a stepped structure, with the portion on the top of the tunnel body being higher than the portion on the side of the tunnel body.

[0012] In one embodiment, a support wall for supporting the retaining wall is fixed between two adjacent retaining walls; the support wall is provided with multiple surfaces and arranged along the length direction of the tunnel body; the two adjacent retaining walls and the two adjacent support walls form a grid slot for storing the large particles trapped by the grid.

[0013] In one embodiment, a geotextile mesh is laid at the bottom of the grid slot for buffering and filtering.

[0014] In one embodiment, a connecting column is arranged at the connection between the support wall and the retaining wall; the highest point of the joint between the support wall and the connecting column is higher than the upper edge of the retaining wall.

[0015] In one embodiment, the frame-type grid dam further comprises a foundation arranged at the bottom of the retaining wall for transmitting load to the foundation; the foundation is a stepped raft foundation or a pile foundation.

[0016] According to one aspect of the present application, one embodiment provides an integrated open-cut tunnel structure for prevention and treatment, comprising:

[0017] the tunnel body;

[0018] the retaining dam as described in any one of the above;

[0019] a drainage culvert embedded in the foundation under the retaining dam and / or the tunnel body; the drainage culvert is provided with a slope for draining the accumulated water in the retaining dam and / or the accumulated water and / or flowing water around the tunnel body.

[0020] In one embodiment, the retaining dam is separated from the surface of the tunnel body; the frame-type grid dam is formed with an arc-shaped edge facing the surface of the tunnel body, which matches the surface of the tunnel body.

[0021] In one embodiment, a waterproof layer is fixedly arranged at the joint between the retaining dam and the surface of the tunnel body.

[0022] In one embodiment, an integrated open-cut tunnel structure for prevention and treatment further comprises an end wall fixed at the end opening of the tunnel body.

[0023] The new structure provided by the above-mentioned embodiments of the present application can realize the prevention and treatment of impact objects generated by geological disasters. In particular, the prevention and treatment integrated open tunnel structure can not only solve the contradiction between the treatment of debris flow disasters and the protection of road traffic facilities, but also greatly improve the space area of road engineering construction, so that the road traffic facilities have a larger living space.

[0024] Specifically, the technical solutions of the above-mentioned embodiments of the present application have the following advantages:

[0025] (1) The dam and the prevention and treatment integrated open tunnel structure are mainly used for preventing and treating various types of debris flow disasters, and also have good protection effect on mountain torrents, rockfalls, small-scale collapses and landslides.

[0026] (2) The prevention and treatment integration in a true sense is realized, the lining + frame type dam structure not only guarantees the traffic safety, but also solves the problem of downstream debris flow disasters at one time, and realizes the sustainable development of engineering and environment.

[0027] (3) The engineering uniformity is high, the traffic protection structure (prevention and treatment integrated open tunnel structure) and the debris flow treatment structure (dam) are consistent in spatial distribution, the two structures cooperate and simultaneously play the protection and treatment functions, the engineering design, construction and later maintenance are convenient for unified management, and the prevention and treatment effect of debris flow disasters is greatly improved.

[0028] (4) The stress environment of the tunnel lining structure of the tunnel body is optimized. Since the frame type dam and the lining structure are independent in stress, under the action of the dam, the stress on the surface of the lining is the pressure of the deposited soil in the groove, the stress form is simple and small, and the design and construction standard of the lining can be reduced to a certain extent.

[0029] (5) The tunnel lining as an open tunnel structure not only eliminates the deep excavation operation, but also saves the artificial backfill process. The coarse particles of the debris flow intercepted in the groove are regarded as natural backfill, and the gravel soil in the groove of the dam body can be used as ballast. It has the effects of improving the specific weight of the dam body, optimizing the structure stress, and improving the stability of the structure.

[0030] (6) The dam and the prevention and treatment integrated open tunnel structure can preferentially consider the combination of prefabricated parts and on-site pouring in construction, which can not only shorten the construction period and improve the quality, but also improve the safety during the construction period.

[0031] (7) The space for road engineering design and construction is widened. Since the present application realizes the integration of traffic and protection functions, the space for line selection in mountainous areas is greatly improved during the line selection, design and construction process. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Figure 1 is a schematic diagram of an integrated open-tunnel tunnel structure for prevention and treatment in an embodiment;

[0033] Figure 2 Figure 2 is a partial schematic diagram of an integrated open-tunnel tunnel structure for prevention and treatment in an embodiment;

[0034] Figure 3 Figure 3 is a partial enlarged view of a retaining wall provided with a drainage opening in an embodiment;

[0035] Figure 4 Figure 4 is a cross-sectional schematic diagram of an integrated open-tunnel tunnel structure for prevention and treatment in an embodiment;

[0036] Figure 5 Figure 5 is a schematic diagram of the overall size of a frame-type grid dam in an embodiment;

[0037] Figure 6 Figure 6 is a partial schematic diagram of a frame-type grid dam in an embodiment;

[0038] Figure 7 Figure 7 is a partial enlarged schematic diagram of a connecting column node in a frame-type grid dam in an embodiment;

[0039] Figure 8 Figure 8 is a schematic diagram of a force path analysis of a frame-type grid dam in an embodiment;

[0040] Figure 9 Figure 9 is a schematic diagram of an overflow state of a debris flow in a working state in an embodiment;

[0041] Figure 10 Figure 10 is a schematic diagram of a force analysis of a retaining wall structure in an embodiment;

[0042] Reference signs:

[0043] 1-frame-type grid dam; 11-connecting column; 12-support wall; 13-retaining wall; 131-grid; 132-drainage opening; 133-semi-open drainage opening; 14-foundation; 15-blocking wall; 16-grid slot; 2-end wall; 3-drainage culvert; 31-tunnel exit; 32-pipe body; 33-catch basin; 4-tunnel body. DETAILED DESCRIPTION

[0044] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0045] In order to better understand the present application by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0046] It should be noted that the terms "first", "second" and the like in the present application are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units need not be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0047] It should be understood that when an element (such as a layer, film, region, or substrate) is described as "on" another element, it can be directly on the other element, or there can be an intermediate element. Moreover, in the present application, when an element is described as "connected" to another element, it can be "directly connected" to the other element, or "connected" to the other element through a third element.

[0048] In order to facilitate the understanding of the present application, the technical solutions of the present application are described below by taking the treatment of debris flow as an example.

[0049] Embodiment one

[0050] Please refer to Figures 1-4 An embodiment provides a retaining dam, comprising: a frame type grid dam 1. In the construction of the retaining dam, the frame type grid dam 1 is arranged on the top and at least one side of a tunnel body 4; generally, the frame type grid dam 1 is arranged on both sides of the tunnel body 4. The frame type grid dam 1 extends along the length direction of the tunnel body 4. Wherein, the frame type grid dam 1 comprises: a retaining wall 13, a drainage port 132 and a grid 131; the retaining wall 13 extends along the length direction of the tunnel body 4 and is used to block the impact object generated by geological disasters; the drainage port 132 is opened on the retaining wall 13; the grid 131 is fixed in the drainage port 132 and is used to intercept large particle objects in the impact object. In an embodiment, the grid 131 is used to block large particle solid objects such as stones in the debris flow, and allows the slurry and fine particle solid objects to flow through (such as Figure 3 As shown).

[0051] In one embodiment, the frame-type grid dam 1 is formed as a stepped structure, with the part on the top of the tunnel body 4 being higher than the part on the side of the tunnel body 4. Specifically, the retaining wall 13 is rigidly connected with the connecting column 11 (described below) to form a blocking transverse wall perpendicular to the flow direction of the debris flow (i.e. an impact object generated by geological disasters), and the retaining walls 13 are arranged in a stepped manner along the direction of the debris flow channel, with the retaining wall 13 on the top of the tunnel hole being the highest, i.e. the top of the frame-type grid dam 1, and the heights of the retaining walls 13 gradually decrease in a stepped manner towards the upstream and downstream (one side of the tunnel body 4). Therefore, the retaining walls 13 are arranged in a trapezoidal dam body as a whole.

[0052] In one embodiment, the connecting column 11 is arranged at the connection between the support wall 12 and the retaining wall 13. The highest point of the joint between the support wall 12 and the connecting column 11 is higher than the upper edge of the retaining wall 13 connected with the connecting column 11. In this way, the stepped structure of the frame-type grid dam 1 is matched, which facilitates the blocking and guiding of the debris flow to the two sides of the frame-type grid dam 1, and the treatment effect of the debris flow is better.

[0053] In one embodiment, the support wall 12 for supporting the retaining wall 13 is fixed between two adjacent retaining walls 13. The support wall 12 is provided with multiple surfaces and is arranged along the length direction of the tunnel body 4. The support wall 12 is rigidly connected with the connecting column 11, and forms a support structure for the retaining wall 13 to maintain the stability of the blocking transverse wall structure and provide a counterforce under the impact of the debris flow, i.e. resist the impact of the debris flow.

[0054] In one embodiment, the grid slot 16 is formed by the two adjacent retaining walls 13 and the two adjacent support walls 12, and is used to store the large particles intercepted by the grid 131. Preferably, a geotextile net is laid at the bottom of the grid slot 16 for buffering and filtering. Specifically, the grid slot 16 is a square structure formed by the retaining wall 13, the support wall 12 and the connecting column 11, and is an empty structure when constructed. The geotextile net is laid at the bottom of the grid slot 16. The grid slot 16 is used to store the coarse-grained solid objects intercepted in the debris flow, and the geotextile net in the grid slot 16 has a buffering and filtering effect.

[0055] In one embodiment, the frame-type grid dam 1 further comprises a foundation 14 arranged at the bottom of the retaining wall 13 for transmitting the load to the foundation. The foundation 14 is a stepped raft foundation or a pile foundation. Generally, the foundation 14 mainly adopts a stepped raft foundation to transmit the load from the connecting column 11, the support wall 12 and other structures to the foundation. Generally, the connecting column 11, the retaining wall 13 and the support wall 12 are all reinforced concrete structures, and transmit the load to the foundation 14.

[0056] Embodiment two

[0057] Please refer to Figures 1-7An embodiment provides a prevention and treatment integrated open tunnel structure with a blocking dam, which is used for road disaster prevention in a debris flow development area in mountainous regions, and is mainly used for protective structures built when roads are exposed to pass through debris flow flow areas. In terms of structure, it includes a tunnel lining of a tunnel body 4, a frame-type grid dam 1, an end wall 2 and a drainage culvert 3.

[0058] Specifically, a prevention and treatment integrated open tunnel structure includes the tunnel body 4, the blocking dam of the first embodiment and the drainage culvert 3; the drainage culvert 3 is pre-buried below the blocking dam and / or the tunnel body 4, and is generally buried in the foundation; the drainage culvert 3 is provided with a slope to facilitate the drainage of accumulated water in the blocking dam and / or the drainage of accumulated water and / or running water around the tunnel body 4.

[0059] Among them, the tunnel body 4 is located near the ground surface or the upper part of the ground surface (the tunnel lining foundation 14 is buried <2m deep) relative to the ground surface elevation. That is, there is no need to carry out large excavation engineering in the open tunnel construction process, and only necessary foundation treatment is needed.

[0060] In an embodiment, the blocking dam is separated from the surface of the tunnel body 4; it can be considered that the blocking dam and the surface of the tunnel body 4 have a gap; of course, a part of the blocking dam is allowed to be in close contact with the surface of the tunnel body 4.

[0061] In an embodiment, the frame-type grid dam 1 is formed with an arc-shaped edge towards the surface of the tunnel body 4, and the arc-shaped edge matches the surface of the tunnel body 4. Specifically, the frame-type grid dam 1 and the lining structure of the tunnel body 4 inside it match in shape, and there is no rigid connection between them, and the tunnel lining itself bears and transmits the load to the foundation. Based on this, it can be understood that a part of the frame-type grid dam 1 can be fixed on the tunnel body 4 and / or a part of it can be in close contact with the side surface of the tunnel body 4. It can even be understood that the frame-type grid dam 1 can be poured integrally with the tunnel body 4.

[0062] However, considering that the tunnel lining is often subjected to the action of water immersion in the debris flow, therefore, compared with the general tunnel lining, a waterproof layer is added between the outer lining and the frame-type grid dam 1. That is, the waterproof layer is fixedly arranged at the joint between the blocking dam and the surface of the tunnel body 4 to achieve the above purpose.

[0063] In one embodiment, the prevention and treatment of an integrated open tunnel structure further comprises an end wall 2 fixed at the end of the tunnel body 4. The end wall 2 is located at both ends of the frame-type grid dam 1, which is a transition structure of the dam body of the frame-type grid dam 1 to the mountain slope on both sides of the debris flow ditch, and also a transition structure of the open tunnel and the hidden tunnel of the tunnel lining. The end wall 2 has the function of keeping the stability of the rock-soil body on both sides of the mountain slope, and also has the function of preventing the scouring of the rock-soil body on both sides of the mountain when the debris flow overflows. The specific form of the end wall 2 is designed according to the terrain, and the height can meet the requirements of the overflow height of the debris flow.

[0064] In one embodiment, the drainage culvert 3 is a concealed project, which is buried in the foundation under the tunnel lining and / or the frame-type grid dam 1. The drainage culvert 3 is mainly divided into three parts: a water collecting well 33, a pipe body 32 and a tunnel body outlet 31. The pipe body 32 is preferably a circular pipe culvert with low friction coefficient, and the slope of the pipe body 32 is as large as possible under the condition (longitudinal slope > 5%), a drainage pipe is connected to the pipe body 32, and the pipe body 32 is connected to the bottom of the grid groove 16 in the frame-type grid dam 1, which is used to drain the accumulated water in the grid groove 16. The water collecting well 33 is used to collect the water accumulated in front of the dam, and can be used to drain the water in the debris flow ditch with perennial water flow. The water collecting well 33 has a certain anti-clogging performance, and the specific form is determined according to the actual situation. The tunnel body outlet 31 is the drainage outlet, and the position and form are determined according to the terrain and the specific parameters of the project.

[0065] Embodiment three

[0066] Please refer to Figures 5-7 In one embodiment, a prevention and treatment integrated open tunnel structure with a blocking dam is provided, and the blocking dam is the blocking dam in embodiment one; the prevention and treatment integrated open tunnel structure is the prevention and treatment integrated open tunnel structure in embodiment two. The prevention and treatment integrated open tunnel structure with the blocking dam has the following characteristics:

[0067] (1) The overall size of the frame-type grid dam 1

[0068] The overall height H of the dam body, that is, the height difference from the top of the highest retaining wall 13 of the dam body to the natural ground; the dam height can be calculated according to the multi-year storage capacity of the blocking dam first. If the calculated storage capacity dam height is less than the tunnel lining height exceeding the ground surface height plus 1 / 2 of the lining section width, the dam height is designed according to 1 / 3 of the tunnel lining height exceeding the ground surface height plus the lining section width. Otherwise, it is directly designed according to the storage capacity dam height.

[0069] The overall slope of the steps in front of the dam, the dam front retaining wall 13 is the first to accept the impact of debris flow, dam front groove 16 is the first to fill the area of debris flow accumulation, so the dam front retaining wall 13 arranged in the steps of the slope is not too large, by more retaining wall 13 composed of a slower slope can effectively reduce the direct impact of debris flow, and can greatly weaken the impact of debris flow speed, play a role in energy dissipation. But too slow, resulting in huge amount of work, not economic. Therefore, the overall slope of the steps in front of the dam retaining wall 13 than the natural angle of repose of debris flow accumulation 5°-25° is appropriate.

[0070] The overall slope of the steps in front of the dam, the dam front retaining wall 13 is the first to accept the impact of debris flow, dam front groove 16 is the first to fill the area of debris flow accumulation, so the dam front retaining wall 13 arranged in the steps of the slope is not too large, by more retaining wall 13 composed of a slower slope can effectively reduce the direct impact of debris flow, and can greatly weaken the impact of debris flow speed, play a role in energy dissipation. But too slow, resulting in huge amount of work, not economic. Therefore, the overall slope of the steps in front of the dam retaining wall 13 than the natural angle of repose of debris flow accumulation 5°-25° is appropriate.

[0071] (2) retaining wall 13 and support wall 12

[0072] The spacing of the retaining wall 13, the spacing of the retaining wall 13 arrangement should be first selected according to the particle size of the large particles in the debris flow, generally greater than 2~3 times the total median of the coarse particles in the debris flow. Then according to the dam shape and size, the spacing between the retaining wall 13 is comprehensively selected, generally the spacing of the retaining wall 13 can be equal. When the spacing of the retaining wall 13 is determined, the number of the retaining wall 13 is also determined by the overall size of the dam body.

[0073] The spacing of the support wall 12, the support wall 12 is a component that connects the retaining wall 13, optimizes the stress of the retaining wall 13, and maintains the integrity of the dam body. In one embodiment, the spacing between the two adjacent support walls 12 is not less than the spacing between the retaining walls 13, which can generally be 2-5 times the spacing between the retaining walls 13.

[0074] (3) Drainage port 132 in the retaining wall 13

[0075] Because of the multi-faceted retaining wall 13, the size of the drainage port 132 is preferably large and multiple, and it is recommended that the size of the drainage port 132 be greater than 30cm x 30cm, and a steel grille 131 is arranged in the drainage port 132. It is appropriate to arrange multiple drainage ports 132 at different heights in each retaining wall 13, and to arrange multiple semi-open drainage ports 133 at the bottom of the retaining wall 13, which directly contact with the tunnel lining or foundation 14, the purpose is to drain the water in the groove 16 as much as possible.

[0076] Regarding the semi-open drainage port 133, in one embodiment, the semi-open drainage port 133 should communicate with the lowest part of the groove 16 to facilitate the drainage of the accumulated water in the groove 16. In one embodiment, the semi-open drainage port 133 directly penetrates the lower edge of the retaining wall 13, which also facilitates the drainage of the accumulated water in the groove 16.

[0077] (4) Relationship between retaining wall 13 and tunnel lining wall

[0078] In order to make the structure more reasonable and safe, two retaining walls 15 should be set outside the tunnel lining walls on both sides of the tunnel body 4. The retaining walls 15 are in close contact with the tunnel walls to prevent water from entering. The semi-open drainage port 133 is set at the wall shoulder to prevent water accumulation.

[0079] (5) Optimization of overflow path of debris flow on frame-type retaining dam

[0080] The overflow channel is set by the relative height of the structure connection, that is, the connection point of the retaining wall 13 on the connecting column 11 is lower than the connection point of the supporting wall 12 on the connecting column 11, and lower than the top of the connecting column 11. As shown in Figure 7 The debris flow overflows into the lower position groove 16 by passing over the upper edge of the retaining wall 13, and then the debris flow may continue to overflow by passing over the lower position retaining wall 13.

[0081] (6) Foundation 14 of frame-type retaining dam

[0082] The structure form is mainly a stepped raft foundation. The steps are set to increase the grip between the foundation 14 and the ground and improve the anti-sliding stability. If the foundation form cannot meet the requirements, ground anchor rods, anti-sliding piles, and other structures can be added.

[0083] Example Four

[0084] Please refer to Figures 8-10 An embodiment provides a structure stability checking method for checking the prevention and treatment integrated open tunnel structure in Example Two and Example Three.

[0085] The structure stability checking of the prevention and treatment integrated open tunnel structure in Example Two and Example Three needs to be carried out according to the force transmission path. The stress path of the tunnel lining and the frame-type retaining dam 1 structure is independent, so the stability needs to be checked separately. Since the tunnel lining itself is the same as the general tunnel structure, the calculation principle and method are also not much different. The frame-type retaining dam has a more complex function, and its stress path is shown in Figure 8 .

[0086] (1) Debris flow load calculation

[0087] There are many forms of the action of debris flow on the frame-type retaining dam 1. Here, the overflow state on the dam top is taken as an example, as shown in Figure 9 The interaction between the debris flow fluid and the dam body can be divided into three stages:

[0088] 1) Impact stage

[0089] At this stage, the flow direction of debris flow is perpendicular to the retaining wall 13. The load of the framework retaining dam 1 by the debris flow at this stage includes the pressure on the retaining wall 13 and the direct bearing in the vertical direction of the foundation 14.

[0090] 2) Overflow section of dam top

[0091] The horizontal pressure at this stage is borne by the retaining wall 13, and the vertical pressure is borne by the tunnel lining.

[0092] 3) Drop section

[0093] At this stage, the debris flow produces a downward drop movement, and the impact force is divided into horizontal and vertical components. The pressure on the retaining wall 13 and the vertical pressure on the foundation 14 need to be calculated. The load of the structure by the debris flow can be divided into: the dynamic pressure generated by the impact of the debris flow, the static pressure generated by the gravity of the fluid, and the earth pressure generated by the saturated sediment deposited in front of and behind the retaining wall 13.

[0094] As shown in Figure 10 , for a single retaining wall 13 (for example, the ith retaining wall 13, i is a positive integer) in the retaining dam, the dynamic pressure of the debris flow on it can be divided into two amounts, i.e. and , the former is consistent with the impact direction of the debris flow, and the latter is opposite to the flow direction of the debris flow. The size of the dynamic pressure of the debris flow (pressure per unit length of the retaining wall) on the retaining wall 13 is:

[0095]

[0096] In the formula, the dynamic pressure of the debris flow (pressure) is obtained by the existing research on the calculation of the dynamic pressure of the debris flow, or is obtained by field test. and represent the height of the retaining wall 13 directly contacted by the debris flow before and after the retaining wall 13, i.e. the distance from the upper surface of the sediment to the wall head. The static pressure of the debris flow on the retaining wall 13 is related to the depth of the debris flow in the front and rear grooves 16, and the size is:

[0097]

[0098]

[0099] In the formula, is the bulk density of the debris flow, which can be obtained by test or determined by empirical formula.

[0100] The earth pressure of the sediment on the retaining wall 13 is related to the thickness of the sediment in the front and rear grooves 16. Here, the static saturated earth pressure is calculated. For a single retaining wall 13, the size of the earth pressure of the sediment on it is: ​

[0101]

[0102] wherein, is the saturated unit weight of the deposited soil, which is measured by experiment; is the static earth pressure coefficient of the soil body, which is valued in the conventional way.

[0103] The vertical pressure intensity on the top surface of the foundation 14 can be estimated as:

[0104]

[0105] The above is the load calculation for a retaining wall 13. For the frame-type check dam 1, the load of each retaining wall is calculated by a similar method, and finally summed up. The thickness of the deposited soil in each cell 16 increases with the increase of the use time, so multiple calculations can be performed when calculating the load to obtain the most unfavorable load as the basis for the limit design. For the support wall 12, since the flow pressure of the debris flow is small, and the static pressure is generally balanced, it can not be considered separately, and only needs to meet the strength requirement as a stability maintaining member. When the bottom of the cell 16 has no foundation but a tunnel lining; the vertical pressure is treated as an external load of the lining.

[0106] (2) Structural stability checking

[0107] Based on the above load, the stability of the structure of the frame-type check dam 1 can be checked. For the steel and concrete components such as the retaining wall 13, the support wall 12, the connecting column 11, the tunnel lining, and the foundation 14, the design and calculation are based on the principles of reinforced concrete structures and are no different from the bending, shear, and tensile stress checking methods of general soil engineering components.

[0108] In addition, the overall stability of the frame-type check dam 1 needs to be checked, mainly the shear stability checking. For the dam body overturning stability checking, since the dam body here is relatively low, it can be omitted; however, when the dam body is high and steep due to special engineering, the overturning stability checking can be performed. The overall stability checking method of the dam body is consistent with the general checking method of the dam body.

[0109] It is worth noting that when the stepped bottom surface of the foundation 14 cannot meet the shear stability requirements, the form of the foundation 14 can be changed to use a pile foundation; or an anti-slide anchor rod can be added for reinforcement.

[0110] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A barrier dam, characterized in that, Comprising: a frame-type grid dam for being arranged on top and at least one side of a tunnel body; the frame-type grid dam extends along the length direction of the tunnel body; the frame-type grid dam is formed as a stepped structure, the part of the stepped structure on the top of the tunnel body is higher than the part on the side of the tunnel body; wherein the frame-type grid dam comprises: a retaining wall extending along the length direction of the tunnel body and for blocking impact objects generated by geological disasters; a drainage opening arranged on the retaining wall; and a grid fixed in the drainage opening for retaining large particles in the impact objects.

2. A barrier dam according to claim 1, wherein, support walls for supporting the retaining walls are fixed between two adjacent retaining walls; the support walls are arranged along the length direction of the tunnel body; the grid slots are formed by the two adjacent retaining walls and the two adjacent support walls, and the grid slots are used for storing the large particles retained by the grid.

3. A barrier dam according to claim 2, wherein, A geotextile net is laid at the bottom of the grid slots for buffering and filtering.

4. A barrier dam according to claim 2, wherein, A connecting column is arranged at the connection between the support wall and the retaining wall; the highest point of the joint between the support wall and the connecting column is higher than the upper edge of the retaining wall.

5. A barrier dam according to claim 1, wherein, The frame-type grid dam further comprises a foundation arranged at the bottom of the retaining wall for transferring load to the ground; the foundation is a stepped raft foundation or a pile foundation.

6. A one-piece open cut tunnel structure for preventing and treating, characterized by, Comprising: the tunnel body; the dam according to any one of claims 1-5; and a drainage culvert embedded in the ground under the dam and / or the tunnel body; the drainage culvert is provided with a slope for draining water accumulated in the dam and / or water accumulated and / or flowing around the tunnel body.

7. A control integrated type open cut tunnel structure according to claim 6, wherein The dam is separated from the surface of the tunnel body; the frame-type grid dam is formed with an arc-shaped edge towards the surface of the tunnel body, and the arc-shaped edge matches the surface of the tunnel body.

8. A control integrated type open cut tunnel structure according to claim 7, wherein A waterproof layer is fixedly arranged at the joint between the dam and the surface of the tunnel body.

9. A control integrated type open cut tunnel structure according to claim 8, wherein Further comprising an end wall fixed at the end opening of the tunnel body.

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