Underwater foundation trench excavation structure

Abstract

The utility model discloses an underwater foundation trench excavation structure which comprises a plurality of first side slope excavation layers vertically facing a design side slope face on one side of a foundation trench, the bottom face of each first side slope excavation layer is horizontal, the two side faces of each first side slope excavation layer are vertical, one side face of each first side slope excavation layer is vertically aligned with a bottom face side line of a design groove of the foundation trench, and the other side face of each first side slope excavation layer vertically penetrates through the design side slope face of the foundation trench. The width of the first slope excavation layer is sequentially reduced from top to bottom; the bottom face of the first slope excavation layer on the bottommost layer is flush with the bottom face of a design groove of the foundation trench. Preferably, the first side slope excavation layers are sequentially arranged in a stacked mode. The slope is excavated in a stepped mode, namely, the slope face is excavated into the step section, and in consideration that underwater excavation soil is loose and prone to collapse, construction is conducted in an over-excavation and under-compensation mode, so that after a groove naturally collapses, the groove is close to the designed slope, the construction difficulty is lowered, and the slope construction quality is improved; and back silting from the side slope on the bottom surface of the foundation trench can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of immersed tubes, in particular to an underwater foundation trench excavation structure. Background Art

[0002] During the construction of underwater submerged pipes, it is usually necessary to excavate the foundation trench first. Some existing construction plans directly carry out excavation construction according to the designed section of the foundation trench. On the one hand, it is difficult to excavate the slope surface of the foundation trench underwater, and it is not easy to control the accuracy; on the other hand, after the excavated foundation trench is exposed for a certain period of time, the silt on the slope surfaces on both sides can easily roll down to the bottom of the trench, resulting in a large amount of siltation at the bottom of the foundation trench, which requires targeted treatment and affects the construction quality and cycle. Utility Model Content

[0003] The problem to be solved by the utility model is to provide an underwater foundation trench excavation structure, which reduces the construction difficulty, improves the quality of slope construction, and can reduce the silting from the slope on the bottom surface of the foundation trench.

[0004] In order to solve the above technical problems, the utility model provides an underwater foundation trench excavation structure, including a plurality of first side slope excavation layers vertically facing the designed side slope surface on one side of the foundation trench, each of the first side slope excavation layers has a horizontal bottom surface and two vertical side surfaces, and one side surface is vertically aligned with the edge line of the bottom surface of the designed trench of the foundation trench, and the other side surface vertically passes through the designed side slope surface of the foundation trench; the width of the first side slope excavation layer decreases from top to bottom; the bottom surface of the first side slope excavation layer at the bottom layer is flush with the designed trench bottom surface of the foundation trench. Preferably, the first side slope excavation layers are stacked in sequence.

[0005] In the above-mentioned underwater foundation trench excavation structure, a stepped excavation slope is adopted, that is, the slope surface is excavated into a stepped section. The phenomenon that the underwater excavated soil is loose and easy to collapse is fully taken into consideration. The over-excavation and under-filling method is adopted for construction, so that after the slope trench collapses naturally, it is close to the designed slope, thereby reducing the construction difficulty, improving the slope construction quality, and reducing the siltation from the slope on the bottom surface of the foundation trench.

[0006] As an improvement of the underwater foundation trench excavation structure of the utility model, the first slope excavation layers are named as the 1st layer, the 2nd layer, ... the nth layer from top to bottom, then:

[0007] When i=1, 2h>H 1左 >h,2h>H 1右 >h;

[0008] When i=2, 3...n, H i左 =H i右 =2h;

[0009] Among them, H i左 is the left side height of the first slope excavation layer of the i-th layer, Hi右 is the right side height of the first slope excavation layer of the i-th layer.

[0010] Since the top surface of the first slope excavation layer is a water bottom mud surface of varying heights, the heights of the left and right sides of the layer may be inconsistent, but are both between h and 2h, where h is a given value; the top surfaces of the 2nd to nth layers are the bottom surfaces of the corresponding previous layer, that is, they are all horizontal planes, so the thicknesses of the 2nd to nth layers of the first slope excavation layer are consistent, and the heights of the left and right sides are equal to the thickness, both 2h.

[0011] Furthermore, when i=1, 2...n-1, W i -W i+1 =2b; when i=n, ​​W n = b; where W i is the width of the i-th layer.

[0012] The widths of the first slope excavation layers 1 to 1 are an arithmetic progression from top to bottom, with a tolerance of 2b, so that the slope surface can be excavated into a step section, where b is a given value.

[0013] Furthermore, the design slope of the foundation trench is: h / b. Both b and h are given values, which are given according to the design slope. In this way, after the slope surface is excavated into a step section, the over-excavation and under-excavation are equal, and the natural collapse of the trench can make the slope surface close to the design slope.

[0014] As another improvement of the underwater foundation trench excavation structure of the utility model, the underwater foundation trench excavation structure also includes a plurality of trench bottom excavation layers vertically facing the designed trench bottom surface of the foundation trench, the bottom surface of each of the first side slope excavation layers is horizontal, and the two side surfaces are respectively vertically facing an edge line of the designed trench bottom surface of the foundation trench. The trench bottom excavation layer realizes the excavation of the middle part of the foundation trench.

[0015] Preferably, the trench bottom excavation layers are stacked from top to bottom. The top surface of the trench bottom excavation layer is the water bottom mud surface, and the bottom surface of the trench bottom excavation layer is flush with the designed trench bottom surface of the foundation trench.

[0016] Furthermore, the excavation layers at the bottom of each trench are named as the 1st layer, the 2nd layer, ... the nth layer from top to bottom, then:

[0017] When i=1, 4h>H j左 >2.7h,4h>H i右 >2.7h;

[0018] When i=2, 3...n, 4h>H j左 =H i右 >2.7h;

[0019] Among them, H j左is the left side height of the jth trench bottom excavation layer, H j右 is the height of the right side of the j-th trench bottom excavation layer. Since the middle part of the foundation trench does not need to consider the impact of siltation, each layer can be excavated deeper to improve construction efficiency.

[0020] Furthermore, the width of the trench bottom excavation layer is equal to the designed trench bottom width of the foundation trench.

[0021] As another improvement of the underwater foundation trench excavation structure of the utility model, the top surface of the first side slope excavation layer at the top layer is a water bottom mud surface.

[0022] As another improvement of the underwater foundation trench excavation structure of the utility model, the underwater foundation trench excavation structure also includes a plurality of second slope excavation layers vertically facing the designed slope surface on the other side of the foundation trench; the bottom surface of each of the second slope excavation layers is horizontal, the two side surfaces are vertical, and one side surface is vertically aligned with the edge line of the bottom surface of the designed trench of the foundation trench, and the other side surface vertically passes through the designed slope surface of the foundation trench; the width of the second slope excavation layer decreases from top to bottom; the bottom surface of the second slope excavation layer at the bottom layer is flush with the designed trench bottom surface of the foundation trench.

[0023] Furthermore, the bottom surface of each of the second side slope excavation layers is flush with the bottom surface of one of the first side slope excavation layers.

[0024] Furthermore, the two side surfaces of each of the second side slope excavation layers correspond to the two side surfaces of one of the first side slope excavation layers and are symmetrical with respect to the design center plane of the foundation pit.

[0025] The second side slope excavation layer and the first side slope excavation layer are excavated to form stepped slope surfaces on both sides of the foundation trench.

[0026] In summary, the use of the above-mentioned underwater foundation trench excavation structure can reduce the construction difficulty, improve the quality of slope construction, and reduce the siltation from the slope on the bottom surface of the foundation trench. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In the attached picture:

[0028] Figure 1 It is a cross-sectional structural diagram of the foundation trench of the underwater foundation trench excavation structure of the utility model.

[0029] In the figure, 1, the first slope excavation layer; 2, the trench bottom excavation layer; 31, the designed slope surface; 32, the designed trench bottom surface; 33, the designed center surface; 4, the second slope excavation layer; 5, the water bottom mud surface. DETAILED DESCRIPTION

[0030] The specific implementation modes of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these implementation modes is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0031] Example 1

[0032] Figure 1 The utility model shows an underwater foundation trench excavation structure. Figure 1 As shown, a structure with four first side slope excavation layers 1, three trench bottom excavation layers 2 and four second side slope excavation layers 4 is used as an example. The underwater foundation trench excavation structure includes a plurality of first side slope excavation layers 1 that are vertically facing the designed side slope surface 31 on one side of the foundation trench, each first side slope excavation layer 1 has a horizontal bottom surface and two vertical side surfaces, and one side surface is vertically aligned with the edge line of the designed trench bottom surface 32 of the foundation trench, and the other side surface vertically passes through the designed side slope surface 31 of the foundation trench; the width of the first side slope excavation layer 1 decreases from top to bottom; the bottom surface of the bottom first side slope excavation layer 1 is flush with the designed trench bottom surface 32 of the foundation trench.

[0033] Optionally, the first side slope excavation layers 1 are stacked in sequence. The top surface of the topmost first side slope excavation layer 1 is a water bottom mud surface 5 .

[0034] like Figure 1 As shown in the figure, the first slope excavation layers 1 are named as the 1st layer, the 2nd layer, ... the nth layer from top to bottom, then:

[0035] When i=1, 2h>H 1左 >h,2h>H 1右 >h;

[0036] When i=2, 3...n, H i左 =H i右 =2h;

[0037] Among them, H i左 is the height of the left side of the first slope excavation layer 1 of the i-th layer, H i右 is the right side height of the first slope excavation layer 1 of the i-th layer.

[0038] Since the top surface of the first layer of the first slope excavation layer 1 is a water bottom mud surface 5 of varying heights, the heights of the left and right sides of the first layer may be inconsistent, but are both between h and 2h, where h is a given value. The top surfaces of the 2nd to nth layers are the bottom surfaces of the corresponding previous layer, that is, they are all horizontal planes, so the thicknesses of the 2nd to nth layers of the first slope excavation layer 1 are consistent, and the heights of the left and right sides are equal to the thickness, both 2h.

[0039] Optionally, when i=1, 2...n-1, W i -W i+1 =2b; when i=n, ​​W n = b; where W i is the width of the i-th layer.

[0040] The widths of the first slope excavation layer 1, layers 1 to n, are an arithmetic progression from top to bottom, with a tolerance of 2b, so that the slope surface can be excavated into a step section, where b is a given value.

[0041] Optionally, the design slope of the foundation trench is: h / b. b and h are both given values, so that h / b is the given foundation trench design slope. According to the design slope, after the slope surface is excavated into a step section, the over-excavation and under-excavation are equal, and the natural collapse of the excavation can make the slope surface close to the design slope 31. For example: the design slope is given as: 1:3.5, then h can be given as 0.75m, and b can be given as 2.625m accordingly.

[0042] like Figure 1 As shown, the underwater foundation trench excavation structure also includes a plurality of trench bottom excavation layers 2 vertically facing the foundation trench design trench bottom surface 32, the bottom surface of each trench bottom excavation layer 2 is horizontal, and the two side surfaces are vertically facing and aligning one edge of the foundation trench design trench bottom surface 32. The trench bottom excavation layer 2 realizes the excavation of the middle part of the foundation trench.

[0043] Optionally, the trench bottom excavation layers 2 are stacked from top to bottom. The top surface of the trench bottom excavation layer 2 is the water bottom mud surface 5, and the bottom surface of the trench bottom excavation layer 2 is flush with the designed trench bottom surface 32 of the foundation trench.

[0044] Optionally, each trench bottom excavation layer 2 is named as the 1st layer, the 2nd layer, ... the nth layer from top to bottom, then:

[0045] When i=1, 4h>H j左 >2.7h,4h>H i右 >2.7h;

[0046] When i=2, 3...n, 4h>H j左 =H i右 >2.7h;

[0047] Among them, H j左 is the height of the left side of the jth layer of trench bottom excavation layer 2, H j右 It is the height of the right side surface of the j-th trench bottom excavation layer 2.

[0048] Since the top surface of the first layer of the trench bottom excavation layer 2 is a water bottom mud surface 5 of varying heights, the heights of the left and right sides of the first layer may be inconsistent, but are both between 2.7h-4h; where h is a given value. The top surfaces of the 2nd to nth layers correspond to the bottom surfaces of the previous layer, that is, they are all horizontal planes. Therefore, the thickness of the 2nd to nth layers of the trench bottom excavation layer 2 is consistent, and the heights of the left and right sides are equal to the thickness, and are also between 2.7h-4h. In addition, since the middle part of the foundation trench does not need to consider the impact of siltation, each layer can be excavated deeper to improve construction efficiency.

[0049] like Figure 1 As shown, the underwater foundation trench excavation structure also includes a plurality of second slope excavation layers 4 vertically facing the designed slope surface 31 on the other side of the foundation trench; the bottom surface of each second slope excavation layer 4 is horizontal, the two side surfaces are vertical, and one side surface is vertically aligned with the edge line of the designed trench bottom surface 32 of the foundation trench, and the other side surface vertically passes through the designed slope surface 31 of the foundation trench; the width of the second slope excavation layer 4 decreases from top to bottom; the bottom surface of the bottom second slope excavation layer 4 is flush with the designed trench bottom surface 32 of the foundation trench.

[0050] Optionally, the bottom surface of each second side slope excavation layer 4 is flush with the bottom surface of a corresponding first side slope excavation layer 1 .

[0051] Optionally, the two side surfaces of each second side slope excavation layer 4 correspond to the two side surfaces of a first side slope excavation layer 1 and are symmetrical about the design center plane 33 of the foundation trench. The second side slope excavation layer 4 and the first side slope excavation layer 1 are excavated to form stepped slopes on both sides of the foundation trench, so the excavation structures on both sides are also symmetrical about the design center plane 33 of the foundation trench.

[0052] During the specific construction, the dredger is towed to the construction site by the workboat. When the dredger is excavating, the dredger is positioned according to the real-time ship position automatically displayed in the window of the surveying and navigation software. The construction method adopts segmentation, layering, and striping. The excavated silt is transported away by mud transport barges. Segmentation refers to segmented excavation along the length of the foundation trench. The length of the segment mainly considers the moving length of the ship and the length of the excavated foundation trench, which is usually set to 100m. Layering refers to the vertical height direction. The layer thickness of the non-slope top part of the foundation trench is usually controlled at 2 to 3m, and the layer thickness of the slope top part is usually controlled at 1.5m, that is, h is usually given as 0.75m. Striping refers to the width of the foundation trench. The width of the striping considers the width of the ship, which is usually 10m. The surveyor uses a sounding water lead to check the excavation depth. After digging a bucket position, it moves forward. After digging a ship position, it moves to another ship position for excavation. When the dredger moves, it must be accurately positioned and the distance of the moving ship must be controlled to avoid missing excavation. After the segmented excavation of the foundation pit is completed, the segmented elevation measurement is carried out. If shallow spots or missed excavations are found, additional excavation is carried out in time to ensure the excavation quality.

[0053] Specifically, during the layered excavation, since the layer thickness at the top of the trench bottom surface is greater than the thickness of the partial layer at the top of the slope, the excavation progress at the top of the trench bottom surface is faster than that at both sides. In order to ensure the construction quality, the layered excavation is carried out according to the first slope excavation layer 1 or the second slope excavation layer 4, ensuring that the layer at the top of the trench bottom surface corresponding to the excavation position is excavated when each layer is excavated in sequence. For example:

[0054] First, excavate the first layer: excavate from the top first side slope excavation layer 1, then excavate the top trench bottom excavation layer 2, and finally excavate the top second side slope excavation layer 4;

[0055] Then excavate the second layer: excavate from the first side slope excavation layer 1 of the second layer, and then if the mud surface at the top of the designed groove bottom surface 32 is lower than the bottom surface of the first side slope excavation layer 1 of the second layer, then excavate the second side slope excavation layer 4 of the second layer; if the mud surface at the top of the designed groove bottom surface 32 is higher than the bottom surface of the first side slope excavation layer 1 of the second layer, then it is necessary to excavate one layer of groove bottom excavation layer 2 downward, and then excavate the second side slope excavation layer 4 of the second layer;

[0056] Then the third layer is excavated: ..., and so on, until the last layer is excavated: excavation from the first slope excavation layer 1 at the bottom, .... After the construction is completed, the slope surface is excavated into a step section, so that the excavation groove collapses naturally and approaches the designed slope surface 31.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit its protection scope. Although the utility model is described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the utility model, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the utility model, but these changes, modifications or equivalent substitutions are all within the protection scope of the pending claims of the utility model.

Claims

1. An underwater foundation trench excavation structure, characterized in that: It comprises a plurality of first side slope excavation layers (1) vertically facing a designed side slope surface (31) on one side of a foundation trench, wherein the bottom surface of each first side slope excavation layer (1) is horizontal, the two side surfaces are vertical, one side surface is vertically aligned with the edge line of the designed trench bottom surface (32) of the foundation trench, and the other side surface vertically passes through the designed side slope surface (31) of the foundation trench; the width of the first side slope excavation layer (1) decreases from top to bottom; the bottom surface of the first side slope excavation layer (1) at the bottom layer is flush with the designed trench bottom surface (32) of the foundation trench.

2. The underwater trench excavation structure according to claim 1, characterized in that: The first slope excavation layers (1) are named as the 1st layer, the 2nd layer, ... the nth layer from top to bottom, then: When i=1, 2h>H 1左 >h,2h>H 1右 >h; When i=2, 3...n, H i左 =H i右 =2h; Among them, H i左 is the left side height of the first slope excavation layer (1) of the i-th layer, H i右 is the right side height of the first slope excavation layer (1) of the i-th layer.

3. The underwater trench excavation structure according to claim 2, characterized in that: When i=1, 2...n-1, W i -W i+1 =2b; When i = n, W n = b; where W i is the width of the i-th layer.

4. The underwater trench excavation structure according to claim 3, characterized in that: The design slope of the foundation pit is: h / b.

5. The underwater foundation trench excavation structure according to claim 2, characterized in that: It also includes a plurality of trench bottom excavation layers (2) vertically facing the designed trench bottom surface (32) of the foundation trench, wherein the bottom surface of each trench bottom excavation layer (2) is horizontal, and the two side surfaces are respectively vertically facing and aligned with one edge of the designed trench bottom surface (32) of the foundation trench.

6. The underwater foundation trench excavation structure according to claim 5, characterized in that: From top to bottom, the trench bottom excavation layers (2) are named as the 1st layer, the 2nd layer, ... the nth layer, then: When i=1, 4h>H j左 >2.7h,4h>H j右 >2.7h; When i=2, 3...n, 4h>H j左 =H i右 >2.7h; Among them, H j左 is the left side height of the jth trench bottom excavation layer (2), H j右 is the right side height of the jth trench bottom excavation layer (2).

7. The underwater foundation trench excavation structure according to claim 1, characterized in that: The top surface of the first side slope excavation layer (1) at the top layer is a water bottom mud surface (5).

8. The underwater foundation trench excavation structure according to claim 1, characterized in that: It also includes a plurality of second side slope excavation layers (4) vertically facing the designed side slope surface (31) on the other side of the foundation trench; the bottom surface of each second side slope excavation layer (4) is horizontal, the two side surfaces are vertical, one side surface is vertically aligned with the edge line of the designed trench bottom surface (32) of the foundation trench, and the other side surface vertically passes through the designed side slope surface (31) of the foundation trench; the width of the second side slope excavation layer (4) decreases from top to bottom; the bottom surface of the second side slope excavation layer (4) at the bottom layer is flush with the designed trench bottom surface (32) of the foundation trench.

9. The underwater trench excavation structure according to claim 8, characterized in that: The bottom surface of each of the second side slope excavation layers (4) is flush with the bottom surface of one of the first side slope excavation layers (1).

10. The underwater foundation trench excavation structure according to claim 8, characterized in that: The two side surfaces of each of the second side slope excavation layers (4) correspond to the two side surfaces of one of the first side slope excavation layers (1) and are symmetrical with respect to the designed central plane (33) of the foundation trench.

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