CN115613583B - Offshore area rock foundation pit and construction method - Google Patents
Offshore area rock foundation pit and construction method Download PDFInfo
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- CN115613583B CN115613583B CN202211612004.6A CN202211612004A CN115613583B CN 115613583 B CN115613583 B CN 115613583B CN 202211612004 A CN202211612004 A CN 202211612004A CN 115613583 B CN115613583 B CN 115613583B
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
- E02D17/04—Bordering surfacing or stiffening the sides of foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D27/00—Foundations as substructures
- E02D27/32—Foundations for special purposes
- E02D27/52—Submerged foundations, i.e. submerged in open water
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D29/00—Independent underground or underwater structures; Retaining walls
- E02D29/02—Retaining or protecting walls
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D29/00—Independent underground or underwater structures; Retaining walls
- E02D29/02—Retaining or protecting walls
- E02D29/0258—Retaining or protecting walls characterised by constructional features
- E02D29/0266—Retaining or protecting walls characterised by constructional features made up of preformed elements
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Abstract
The application relates to the technical field of offshore area ocean engineering construction, and particularly provides an offshore area rock foundation pit and a construction method thereof. Offshore area rock foundation ditch sets up in the offshore area seabed, and the offshore area seabed includes the rock layer of lower floor and the silt layer on upper strata, and offshore area rock foundation ditch includes: the pit body penetrates through the sediment layer and is at least partially positioned in the rock layer; the mud blocking structure surrounds the pit body and penetrates through the sediment layer, the cross section of the mud blocking structure in the direction vertical to the thickness direction of the pit body is spindle-shaped, and the axis of the mud blocking structure extends in the first direction; the first direction is parallel to the direction of ocean current; a plurality of first spud piles around the pit body are located between the pit body and the mud stopping structure, and at least part of the first spud piles penetrate into the rock layer along the depth direction of the pit body. This application can reduce the silt that gets into offshore area rock foundation ditch under the prerequisite of guaranteeing that offshore area rock foundation ditch possesses good structural strength, improves the efficiency of construction of offshore area rock foundation ditch, the follow-up use of offshore area rock foundation ditch of being convenient for.
Description
Technical Field
The application relates to the technical field of offshore area ocean engineering construction, in particular to an offshore area rock foundation pit and a construction method thereof.
Background
With the increasing abundance of ocean development technologies, buildings, such as ocean tunnel bridge buildings, harbor buildings, offshore power station buildings, coastal dam buildings, offshore drilling platforms, etc., need to be built in the offshore area, and foundation pits need to be excavated and built on the seabed of the offshore area corresponding to the construction position before the buildings are built, so that the building structure is stable.
However, the undersea of the offshore region is characterized by silt in the upper layer and rock in the lower layer, so that the construction difficulty of the foundation pit is greatly increased. In addition, because there is the stormy waves in the offshore area, the construction process can be influenced by ocean currents, especially the washed silt can enter the foundation pit to cause the foundation pit to be buried by the silt, influences the construction process of follow-up building.
Disclosure of Invention
In view of the above analysis, the present application aims to provide a rock foundation pit in the offshore region and a construction method thereof, which can simplify the construction process of the rock foundation pit in the offshore region and improve the structural strength of the rock foundation pit in the offshore region.
The purpose of the application is mainly realized by the following technical scheme:
on the one hand, this application embodiment provides an offshore area rock foundation ditch, sets up in the offshore area seabed, and the offshore area seabed includes the lithosphere of lower floor and the silt layer on upper strata, and offshore area rock foundation ditch includes: the pit body penetrates through the sediment layer and is at least partially positioned in the rock layer, so that the bottom of the pit body is positioned in the rock layer; the mud blocking structure surrounds the pit body and penetrates through the sediment layer, the cross section of the mud blocking structure in the direction vertical to the thickness direction of the pit body is spindle-shaped, and the axis of the mud blocking structure extends in the first direction; the first direction is parallel to the direction of ocean current; a plurality of first spud piles around the pit body are located between the pit body and the mud stopping structure, and at least part of the first spud piles penetrate into the rock layer along the depth direction of the pit body.
According to an aspect of an embodiment of the present application, a fender structure includes: at least part of the first frameworks penetrate into the rock layer, so that part of the first frameworks are inserted into the rock layer and fixed with the rock layer; the second frameworks are vertical to the depth direction of the pit body and are annular and connected with all the first frameworks; and the fender covers the outer side of a curved surface formed by the first framework and the second framework and penetrates through the silt layer.
According to an aspect of the embodiment of the present application, the fender forms a side surface of a platform body having a spindle-shaped cross section, and the cross section of the platform body is large in the upper portion and small in the lower portion.
According to an aspect of the embodiment of the present application, the method further includes: the silt wall is positioned on the silt layer and forms a part of the side wall of the pit body; the silt wall is provided with a second fixing pile perpendicular to the outside of the thickness direction of the pit body, and the second fixing pile is inserted into the silt layer.
According to an aspect of the embodiment of the application, gravel is filled between the silt wall and the mud guard.
On the other hand, the embodiment of the application also provides a method for building the offshore region rock foundation pit, which is used for building the offshore region rock foundation pit according to the embodiment of the application; the method for constructing the rock foundation pit in the offshore region comprises the following steps: step 1, fixedly arranging a mud blocking structure at the periphery of a building position of a rock foundation pit in an offshore area; step 2, inserting a first fixing pile between the building position of the rock foundation pit in the offshore area and the mud blocking structure; step 3, sucking out a sediment layer at the building position of the rock foundation pit in the near sea area to expose the rock layer; step 4, excavating on the exposed rock layer to form a pit body; and 5, reinforcing the pit body to form the offshore area rock foundation pit with a stable structure.
According to another aspect of an embodiment of the present application, step 1 comprises: step 1.1, determining the ocean current direction of the building position of the rock foundation pit in the offshore area as a first direction; and 1.2, penetrating the mud blocking structure through the sediment layer, penetrating the mud blocking structure into the rock layer, and enabling the cross section of the mud blocking structure to be in a spindle shape, wherein the axis extends along the first direction.
According to another aspect of the embodiments of the present application, step 1 further includes: the ratio of the minimum distance from the mud blocking structure to the building position of the rock foundation pit in the offshore region to the radius of the circumscribed circle of the rock foundation pit in the offshore region is smaller than or equal to a first coefficient, and the minimum distance from the mud blocking structure to the building position of the rock foundation pit in the offshore region is larger than or equal to a first safety distance.
According to another aspect of the embodiments of the present application, step 2 includes: and penetrating the first fixing piles through the sediment layer to penetrate the rock layer, wherein the distance from each first fixing pile to the building position of the rock foundation pit in the offshore area is a first distance, the ratio of the first distance to the radius of the inscribed circle of the rock foundation pit in the offshore area is smaller than or equal to a second coefficient, and the first distance is larger than or equal to a second safety distance.
According to another aspect of the embodiments of the present application, step 3 includes: 3.1, sucking out a sediment layer at the building position of the rock foundation pit in the near sea area; and 3.2, adding broken stones between the mud blocking structure and the first fixing pile.
Compared with the prior art, the application has at least one of the following beneficial effects:
(a) According to the offshore region rock foundation pit, the rock layer and the silt layer around the foundation pit are fixed by arranging the first fixing piles which penetrate through the silt layer and penetrate into the rock layer, so that the structural strength of the offshore region rock foundation pit is ensured;
(b) According to the offshore region rock foundation pit, the mud blocking structure surrounding the pit body is arranged on the outer side of the first fixing pile, so that the scouring of ocean currents on silt can be resisted, and therefore the silt entering the pit body due to the scouring of ocean currents is reduced, and the offshore region rock foundation pit can be conveniently subsequently utilized;
(c) The utility model provides a near sea area rock foundation ditch sets up fender mud structure for the fusiform of coastal current direction for the ocean current can flow smoothly through the both sides of fender mud structure, reduces the impact of ocean current to the incident surface of fender mud structure, reduces the hoarding of silt at the shadow flow face of fender mud structure, and then reduces the influence of ocean current to the foundation ditch.
In the present application, the above technical solutions may be combined with each other to realize more preferable combination solutions. Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the application. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the application, wherein like reference numerals are used to designate like parts throughout the drawings;
fig. 1 is a schematic structural diagram of a rock foundation pit in an offshore region according to an embodiment of the present application;
FIG. 2 is a top view of an offshore area rock foundation pit according to an embodiment of the present application;
FIG. 3 isbase:Sub>A cross-sectional view of section A-A of the offshore area rock foundation pit of the embodiment of the present application shown in FIG. 2;
fig. 4 is a schematic flow chart of a method for constructing a rock foundation pit in an offshore region according to an embodiment of the present application.
Reference numerals:
11. a rock layer; 12. a silt layer;
2. a pit body;
3. a first spud pile;
4. a mud blocking structure; 41. a first skeleton; 42. a second skeleton; 43. a fender;
5. a silt wall;
x, the first direction.
Detailed Description
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the application and together with the description, serve to explain the principles of the application and not to limit the scope of the application.
In the description of the embodiments of the present application, it should be noted that, unless otherwise explicitly stated or limited, the term "connected" should be interpreted broadly, and may be, for example, a fixed connection, a detachable connection, or an integral connection, which may be a mechanical connection, an electrical connection, which may be a direct connection, or an indirect connection via an intermediate medium. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as the case may be.
The terms "top," "bottom," "at 8230; \8230; above," "below," and "at 8230; above" are used throughout the description to refer to the relative positions of the components of the device, such as the relative positions of the top and bottom substrates inside the device. It will be appreciated that the devices are multifunctional, regardless of their orientation in space.
The applicant found that: when an underwater foundation pit is built, two modes of isolated drainage construction or underwater direct construction are generally adopted. The manner of directly constructing the foundation pit underwater can simplify the construction process. However, if the foundation pit is constructed underwater in the offshore area, the geological structure and the ocean current influence the construction of the foundation pit. A typical geological structure of the sea floor in the offshore region is a sediment layer on the upper layer and a rock layer on the lower layer. When the foundation pit is built, silt can flow, so that the excavation of the pit body is influenced. Thereby fixing the periphery of the pit body. In addition, due to the scouring of the ocean currents, the mobility of the silt can be enhanced, and after the foundation pit is built, the silt can even bury the foundation pit gradually along with the reciprocating motion of the ocean currents. In either case, the subsequent utilization of the foundation pit is affected.
In view of the above analysis, the applicant proposes an offshore area rock foundation pit and a construction method thereof, wherein the offshore area rock foundation pit comprises a pit body, a mud blocking structure and a first fixing pile. The first fixing pile surrounds the pit body, and the mud blocking structure surrounds the first fixing pile to form a multilayer structure from inside to outside. The first fixing pile can fix the seabed around the pit body to ensure the structural strength around the seabed, so that the structural strength of the rock foundation pit in the offshore area is ensured. Meanwhile, the construction position that silt enters the rock foundation pit in the offshore region in the foundation pit construction process can be reduced, and therefore the construction efficiency of the foundation pit is improved. The fender mud structure can resist the scouring of ocean current to silt to reduce and wash the silt that the sand got into the hole body because of the ocean current, with the convenience to the follow-up utilization of the offshore area rock foundation ditch of this application. In addition, the mud blocking structure is arranged to be in a fusiform shape along the direction of the ocean current, so that the ocean current can smoothly flow through two sides of the mud blocking structure, the impact of the ocean current on the flow surface of the mud blocking structure is reduced, the accumulation of silt on the flow surface of the mud blocking structure is reduced, and the influence of the ocean current on rock foundation pits in the near sea area is further reduced.
Fig. 1 is a schematic structural diagram of a rock foundation pit in an offshore area according to an embodiment of the present application.
Specifically, referring to fig. 1, the embodiment of the present application provides an offshore area rock foundation pit, which is disposed on the seabed of the offshore area, the seabed of the offshore area includes a rock layer 11 on the lower layer and a sediment layer 12 on the upper layer, and the offshore area rock foundation pit includes: a pit body 2 penetrating through the sediment layer 12 and at least partially located within the rock layer 11 such that the bottom of the pit body 2 is located within the rock layer 11; the mud blocking structure 4 surrounding the pit body 2 penetrates through the sediment layer 12, the cross section of the mud blocking structure 4 along the direction vertical to the thickness direction of the pit body 2 is spindle-shaped, and the axis extends along the first direction X; the first direction X is parallel to the direction of ocean current; a plurality of first spuds 3 surrounding the pit body 2 are located between the pit body 2 and the fender structure 4, and at least part of the first spuds 3 penetrate into the rock layer 11 in the depth direction of the pit body 2.
The offshore area rock foundation pit of the embodiment of the application is built on the seabed of the offshore area, the structure of the seabed comprises a sediment layer 12 located on the upper layer and a rock layer 11 located on the lower layer, the structural strength of the rock layer 11 is large, the structure is stable, the structural strength of the sediment layer 12 is low, and certain fluidity is shown under the action of ocean current. The offshore area rock foundation pit of this application embodiment runs through silt layer 12, and penetrates rock layer 11 to guarantee that the offshore area rock foundation pit of this application embodiment possesses certain structural strength.
The pit body 2 is a main structure of the offshore area rock foundation pit of the embodiment of the present application, and other buildings, such as a pier of an ocean bridge, a pile body of a harbor dock, and a support of an offshore platform, can be built in the offshore area rock foundation pit of the embodiment of the present application subsequently. The opening of the top of the pit body 2 is located on the upper surface of the sediment layer 12, and a part of the pit body 2 is located on the rock layer 11, that is, the bottom of the pit body 2 is located on the rock layer.
The first fixing piles 3 are provided in plurality, and are arranged around the outer side of the pit body 2. The first fixing pile 3 penetrates through the sediment layer 12 and into the rock layer 11, and is fixed to the rock layer 11 to fix the seabed around the pit body 2. The arrangement shape of the plurality of first spuds 3 is the same as the shape of the pit body 2, so that the distance from each first spud 3 to the pit body 2 is substantially equal, thereby making the fixing effect of the plurality of first spuds 3 to the pit body 2 uniform. In addition, first spud pile 3 also can play certain fixed action to silt layer 12 to reduce the silt entering hole body 2 around the hole body 2, make things convenient for the follow-up use of the offshore area rock foundation ditch of this application embodiment. When the pit body 2 is excavated and built, silt entering the building area of the offshore area rock foundation pit of the embodiment can be reduced, and therefore the excavating efficiency of the pit body 2 is improved.
The mud guard structure 4 is around the peripheral side of a plurality of first spud piles 3, and can withstand the impact of ocean currents. Consequently, after the offshore region rock foundation pit of this application embodiment was accomplished and is built, fender mud structure 4 can reduce silt and follow the ocean current and get into the pit body 2 to make things convenient for the follow-up use of offshore region rock foundation pit of this application embodiment. In addition, the cross sectional shape that fender mud separated the structure is the fusiform that sets up along first direction X, first direction X is parallel with the direction of ocean current, make the ocean current flow through from the both sides of fender mud structure 4, reduce the impact of ocean current to fender mud structure 4, the impact of ocean current to fender mud structure 4 arouses the piling up of silt easily, consequently, fusiform fender mud structure 4 can reduce silt effectively and pile up around the near sea area rock foundation ditch of this application embodiment, also can reduce silt and get into the pit body 2.
It should be noted that the direction of the ocean current is difficult to be constant all the year round, and usually varies within a certain angle range, and in this case, the direction corresponding to the center line of the angle range may be the direction of the ocean current. At this time, the impact of the sea current on the mud guard structure 4 can be maintained within a low range.
In addition, the first fixing piles 3 and the mud blocking structures 4 do not need to extend out of the sea surface, and only need to extend out of the seabed by a certain height.
Fig. 2 is a plan view of an offshore area rock foundation pit according to an embodiment of the present application. Fig. 3 isbase:Sub>A cross-sectional view ofbase:Sub>A sectionbase:Sub>A-base:Sub>A of the offshore area rock foundation pit of fig. 2 according to the embodiment of the present application.
Further, with reference to fig. 2 and 3, the fender structure 4 includes: a plurality of first frameworks 41 surrounding the pit body 2, wherein at least part of the first frameworks 41 penetrate into the rock layer 11, so that a part of the first frameworks 41 are inserted into the rock layer 11 and fixed with the rock layer 11; a plurality of second frameworks 42 vertical to the depth direction of the pit body 2, wherein the second frameworks 42 are in a ring shape and are connected with all the first frameworks 41; and a fender 43 covering the outside of the curved surface formed by the first frame 41 and the second frame 42, wherein the fender 43 penetrates the silt layer 12.
The first framework 41 penetrates the sediment layer 12 in the depth direction of the pit body 2 and penetrates the rock layer 11, and equivalently, a part of the first framework 41 is inserted into the rock layer 11, so that the first framework 41 is fixedly connected with the rock layer 11. Meanwhile, the first framework 41 is fixed to the rock layer 11 to provide support for the fender structure 4 in the depth direction of the pit body 2. The second frame 42 is annular, each second frame 42 is fixedly connected with each first frame 41, and the second frame 42 inclines relative to the first frame 41. The first and second skeletons 41 and 42 can form a stable net structure to support the fender structure 4 and to some extent provide a supporting force sufficient to resist the impact of the sea currents. The fender 43 covers the structure formed by the first frame 41 and the second frame 42, so that the fender 43 forms a curved outer peripheral surface having a spindle-shaped cross section. The mud guard 43 is used for resisting sea currents and reducing silt entering the pit body 2, therefore, the mud guard 43 only needs to penetrate through the silt layer 12, can abut against the rock layer 11 and can penetrate into the rock layer 11.
Further, the fender 43 forms a side surface of a platform body having a spindle-shaped cross section, and the cross section of the platform body is large in the upper portion and small in the lower portion.
The mud guard structure 4 is designed into a platform body with a small upper part and a large lower part, so that the reflected flow generated when the ocean current impacts the mud guard structure 4 faces the direction deviating from the seabed, and even if the reflected flow and the incident flow are superposed at the position far away from the seabed to form turbulent flow, the turbulent flow cannot disturb the sediment of the sediment layer 12 at the position close to the seabed. Therefore, the impact of ocean currents on the mud blocking structure 4 is further reduced, the sand and the mud entering the pit body 2 are reduced, the pit body 2 is further protected, and the building which can be built subsequently by the pit body 2 is further protected.
Furthermore, the height of the mud-guard structure 4 protruding from the seabed should not be higher than the first spud 3. When the sea current flows through the top opening of the mudguard structure 4, the sea current will generate turbulence at the opening of the mudguard structure 4. Because first spud pile 3 highly is higher than fender mud structure 4, first spud pile 3 can stretch out from the open-top of fender mud structure 4 to hinder the ocean current to produce the torrent, and then weaken the ocean current and at the inside disturbance to silt of fender mud structure 4, further reduce the silt that gets into the pit body 2. The depth of insertion of the retaining structure 4 into the rock layer 11 should not be deeper than the depth of insertion of the first spud 3 into the rock layer 11, so as to reduce the effect of local structure penetration into the rock layer 11 on the anchoring effect of the first spud 3 to the seabed. First spud pile 3 inserts lithosphere 11 along vertical direction for a plurality of first spud piles 3 form cylindrically, thereby improve the fixed effect to silt layer 12 and lithosphere 11.
Further, the offshore area rock foundation pit of this application embodiment still includes: a silt wall 5 which is positioned on the silt layer 12 and forms a part of the side wall of the pit body 2; the silt wall 5 is provided with a second fixed pile which is vertical to the outside of the thickness direction of the pit body 2, and the second fixed pile is inserted into the silt layer 12.
Furthermore, gravel is filled between the silt wall 5 and the mud guard 43. Because silt layer 12 demonstrates certain mobility under the ocean current effect, consequently, pack the rubble between silt wall 5 and fender 43, can make silt be located the hole between the rubble to weaken silt because of the mobility that ocean current produced, and then reduce the silt that gets into pit body 2. In addition, the crushed stone can weaken the ocean current near the silt layer 12, and further reduce silt entering the pit body 2 due to the ocean current.
Fig. 4 is a schematic flow chart of a method for constructing a rock foundation pit in an offshore region according to an embodiment of the present application.
Referring to fig. 4, an embodiment of the present application further provides a method for constructing an offshore area rock foundation pit, which is used for constructing the offshore area rock foundation pit according to the foregoing embodiment of the present application.
Specifically, the method for constructing the rock foundation pit in the offshore region comprises the following steps:
step 1, the mud blocking structure 4 is fixedly arranged on the periphery of the building position of the rock foundation pit in the offshore area.
The mud blocking structure 4 can resist ocean current impact after the offshore area rock foundation pit is built, so that silt entering the offshore area rock foundation pit is reduced, ocean current impact can be resisted in the process of building the offshore area rock foundation pit, and the building operation efficiency is improved.
The ratio of the minimum distance from the mud blocking structure 4 to the building position of the rock foundation pit in the offshore region to the radius of the circumscribed circle of the rock foundation pit in the offshore region is smaller than or equal to a first coefficient, and the minimum distance from the mud blocking structure 4 to the building position of the rock foundation pit in the offshore region is larger than or equal to a first safety distance. The distance between fender mud structure 4 and the construction position of offshore area rock foundation ditch should not be too big, and too big distance can lead to the sea current can get into fender mud structure 4 inboard via the open-top of fender mud structure 4, still can make silt get into in the hole body 2 of offshore area rock foundation ditch. The distance between the fender structure 4 and the building position of the rock foundation pit in the offshore region is not too small, and the too small distance can cause the fender structure 4 to influence the structural strength of the seabed around the pit body 2. Wherein the first coefficient may be 0.2-0.3, and the first safety distance may be 1-2m.
Step 1.1, determining that the ocean current direction of the building position of the rock foundation pit in the offshore area is a first direction X.
The offshore region rock foundation pit is impacted by ocean currents in the process of building the offshore region rock foundation pit and after the offshore region rock foundation pit is built, and therefore the direction of the ocean currents needs to be determined so as to reduce the negative influence of the ocean currents.
In addition, the construction position of the offshore region rock foundation pit and design parameters including, but not limited to, depth and cross-sectional dimensions need to be predetermined before the offshore region rock foundation pit is constructed.
Step 1.2, penetrating the mud blocking structure 4 through the sediment layer 12, penetrating the rock layer 11, and enabling the cross section of the mud blocking structure 4 to be spindle-shaped, wherein the axis extends along the first direction X.
The mud blocking structure 4 is built along the direction of the ocean current, and after the subsequent offshore area rock foundation pit building process and offshore area rock foundation pit building, the mud blocking structure 4 can resist the impact of the ocean current, so that the influence of the ocean current on the process of building the offshore area rock foundation pit is reduced, and the offshore area rock foundation pit can be conveniently used for the subsequent process after the offshore area rock foundation pit is built. Because the fender mud structure 4 adopts fusiform, most ocean currents can flow away via the both sides of fender mud structure 4 to reduce the impact of ocean currents to fender mud structure 4, reduce the influence of ocean currents to fender mud structure 4 inboard.
And 2, inserting the first fixing pile 3 between the building position of the rock foundation pit in the offshore area and the mud blocking structure 4.
The first fixing piles 3 can fix the seabed structure around the building position of the rock foundation pit in the offshore region, and when the pit body 2 is subsequently excavated, the sediment entering the excavation area is reduced, so that the operation efficiency of the process of subsequently excavating the pit body 2 is higher. In addition, after the offshore area rock foundation pit is built, the structural strength around the pit body 2 can be ensured, and the possibility of deformation of the pit body 2 is reduced, so that the offshore area rock foundation pit can be conveniently used subsequently.
And penetrating the first fixing piles 3 through the sediment layer 12 and the rock layer 11, wherein the distance from each first fixing pile 3 to the building position of the rock foundation pit in the offshore region is a first distance, the ratio of the first distance to the radius of an inscribed circle of the rock foundation pit in the offshore region is smaller than or equal to a second coefficient, and the first distance is larger than or equal to a second safety distance. The first distance is not too large, the first fixing piles 3 can be far away from the pit body 2 due to the too large first distance, the fixing effect of the first fixing piles 3 on the seabed around the pit body 2 is reduced, and the structural strength of the pit body 2 is weakened. First distance should not too little, and the first distance of undersize can lead to first spud pile 3 to influence the follow-up use of offshore area rock foundation ditch. Wherein the second coefficient may be 0.05-0.1, the second safety distance may be 0.5-1m,
and 3, sucking out the sediment layer 12 at the building position of the rock foundation pit in the near sea area to expose the rock layer 11.
Due to the arrangement of the mud blocking structure 4 and the first fixing pile 3, in the process of sucking mud and sand, the mud and sand entering the building position of the rock foundation pit in the offshore region from the outside can be reduced, and therefore the operation efficiency is improved.
And 3.1, sucking out the sediment layer 12 at the building position of the rock foundation pit in the near sea area.
Can carry out the excavation of certain degree to silt layer 12 earlier, the rethread suction apparatus goes out the remaining silt suction in silt layer 12 to realize exposing of rock stratum 11.
And 3.2, adding broken stones between the mud blocking structure 4 and the first fixing pile 3.
Make silt be located the hole between the rubble to weaken silt and because of the mobility that the ocean current produced, and then reduce the silt that gets into pit body 2, further improve the operating efficiency.
And 4, excavating the exposed rock layer 11 to form the pit body 2.
When the rock layer 11 has been exposed, the rock layer 11 may be excavated directly using an excavating device to form the pit body 2.
And 5, reinforcing the pit body 2 to form the offshore area rock foundation pit with a stable structure.
A silt wall 5 may be provided on the side wall of the pit body 2 to further reduce silt entering the pit body 2. When the pit body 2 is reinforced, deformation prediction can be performed on the rock foundation pit in the offshore region in advance, and the position where deformation is more likely to occur is reinforced. Illustratively, the MSD method may be employed to predict deformation of a rock excavation in the offshore region. The stress and strain change around the pit body 2 after the offshore region rock foundation pit is built is analyzed by analyzing the stress around the pit body 2 after the offshore region rock foundation pit is excavated and the stress change before excavation. According to the law of conservation of energy, the strain energy around the pit body 2, the gravitational potential energy of the sediment and the rock around the pit body 2, and the strain energy of the stressed bending of the first fixing pile 3 are conserved in energy, and the displacement and the deformation which possibly occur around the pit body 2 can be obtained, so that the region which is easy to generate obvious deformation is judged, and the region which is easy to generate obvious deformation is emphasized and reinforced.
In addition, there may be a time interval between the completion of the construction of the offshore region rock foundation pit and the subsequent use of the offshore region rock foundation pit. Therefore, the offshore area rock foundation pit can be detected, and excessive deformation of the offshore area rock foundation pit can be found in time, so that subsequent use of the offshore area rock foundation pit can be smoothly carried out.
In summary, the embodiment of the application provides a rock foundation pit in an offshore area and a construction method thereof, wherein a rock stratum and a silt stratum around the foundation pit are fixed by arranging a first fixing pile which penetrates through the silt stratum and penetrates through the rock stratum, so that the structural strength of the rock foundation pit in the offshore area is ensured; the mud blocking structure surrounding the pit body is arranged on the outer side of the first fixing pile, so that the scouring of ocean currents on silt can be resisted, the silt entering the pit body due to the scouring of ocean currents is reduced, and the subsequent utilization of the rock foundation pit in the offshore area is facilitated; the mud blocking structure is arranged to be fusiform along the direction of the ocean current, so that the ocean current can smoothly flow through two sides of the mud blocking structure, the impact of the ocean current on the upstream side of the mud blocking structure is reduced, the accumulation of silt on the shadow flow side of the mud blocking structure is reduced, and the influence of the ocean current on a foundation pit is further reduced.
The above description is only for the preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application.
Claims (8)
1. The utility model provides an offshore area rock foundation ditch sets up in the offshore area seabed, the offshore area seabed includes the rock layer of lower floor and the silt layer on upper strata, its characterized in that, offshore area rock foundation ditch includes:
a pit body penetrating through the sediment layer and at least partially located in the rock layer;
the mud blocking structure surrounds the pit body and penetrates through the silt layer, the cross section of the mud blocking structure in the direction vertical to the thickness direction of the pit body is in a spindle shape, and the axis of the mud blocking structure extends in the first direction; the first direction is parallel to the direction of ocean current; the mud blocking structure is used for resisting the impact of sea current and reducing the entrance of silt into the pit body;
a plurality of first fixing piles surrounding the pit body and located between the pit body and the mud stopping structure, wherein at least part of the first fixing piles penetrate into the rock stratum along the depth direction of the pit body; the distance from each first fixing pile to the pit body is equal;
the fender mud structure includes:
a plurality of first skeletons surrounding the pit body, at least a portion of the first skeletons penetrating the rock layer;
the second frameworks are annular, each second framework is fixedly connected with each first framework, and the second frameworks incline relative to the first frameworks;
the mud guard covers the outer side of a curved surface formed by the first framework and the second framework, and penetrates through the silt layer;
the fender forms the side of the platform body with the spindle-shaped cross section, and the cross section of the platform body is small in size and large in size.
2. The offshore region rock foundation pit of claim 1, further comprising:
the silt wall is positioned on the silt layer and forms a part of the side wall of the pit body; the silt wall is equipped with perpendicularly the outside second spud pile of hole body thickness direction, the second spud pile inserts the silt layer.
3. The offshore region rock foundation pit as claimed in claim 2, wherein gravel is filled between the silt wall and the mud guard.
4. A method of constructing an offshore rock foundation pit, for constructing an offshore rock foundation pit according to any one of claims 1 to 3; the method for constructing the rock foundation pit in the offshore region comprises the following steps:
step 1, fixedly arranging the mud blocking structure at the periphery of the construction position of the rock foundation pit in the offshore area;
step 2, inserting the first fixing pile between the construction position of the rock foundation pit in the offshore area and the mud blocking structure;
step 3, sucking out the sediment layer at the building position of the rock foundation pit in the offshore area to expose the rock layer;
step 4, excavating on the exposed rock stratum to form the pit body;
and 5, reinforcing the pit body to form the rock foundation pit in the offshore area with a stable structure.
5. The method for constructing a rock foundation pit in the offshore region according to claim 4, wherein the step 1 comprises:
step 1.1, determining the ocean current direction of the building position of the rock foundation pit in the offshore area as the first direction;
step 1.2, penetrating the mud blocking structure through the sediment layer, penetrating the rock layer, and enabling the cross section of the mud blocking structure to be in a spindle shape, wherein the axis extends along a first direction.
6. The method for constructing a rock foundation pit in the offshore region according to claim 5, wherein the step 1 further comprises:
the ratio of the minimum distance from the mud blocking structure to the building position of the rock foundation pit in the offshore region to the radius of the circumscribed circle of the rock foundation pit in the offshore region is smaller than or equal to a first coefficient, and the minimum distance from the mud blocking structure to the building position of the rock foundation pit in the offshore region is larger than or equal to a first safety distance;
the first coefficient is 0.2-0.3, and the first safety distance is 1-2m.
7. The method for constructing a rock foundation pit in the offshore region according to claim 4, wherein the step 2 comprises:
penetrating the first fixing piles through the sediment layer, penetrating the first fixing piles into the rock layer, and enabling the distance from each first fixing pile to the building position of the rock foundation pit in the offshore region to be a first distance, wherein the ratio of the first distance to the radius of an inscribed circle of the rock foundation pit in the offshore region is smaller than or equal to a second coefficient, and the first distance is larger than or equal to a second safety distance;
the second coefficient is 0.05-0.1, and the second safety distance is 0.5-1m.
8. The method for constructing a rock foundation pit in the offshore region according to claim 4, wherein the step 3 comprises:
step 3.1, sucking out the sediment layer at the building position of the rock foundation pit in the offshore area;
and 3.2, adding broken stones between the mud blocking structure and the first fixing pile.
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| CN103243725A (en) * | 2013-04-26 | 2013-08-14 | 中铁隧道集团有限公司 | Offshore foundation pit cofferdam construction technology |
| CN109706936A (en) * | 2018-10-12 | 2019-05-03 | 武汉市市政建设集团有限公司 | A kind of bridge pier foundation pit multistage support structure |
| CN210658383U (en) * | 2019-09-17 | 2020-06-02 | 浙江交工集团股份有限公司 | Silt deep water big rivers foundation ditch combination is strutted |
| CN113202130A (en) * | 2021-06-04 | 2021-08-03 | 中国华能集团清洁能源技术研究院有限公司 | High-rise-network-format offshore wind power foundation anti-scouring system and method |
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