Composite foundation structure of barrel type foundation and full-length sand pile

Abstract

The utility model discloses a composite foundation structure of a barrel type foundation and a full-length sand pile. The composite foundation structure comprises the barrel type foundation and the full-length sand pile, wherein the barrel type foundation is provided with a lower barrel and an upper barrel. The inner cavity of the lower barrel is divided into a plurality of compartments by arranging a plurality of partition walls; the full-length sand piles are hit in a soft clay foundation on the surface layer of a seabed, and the top elevation is flush with the seabed surface; the full-length sand pile is divided into a plurality of sand pile units, and the arrangement positions of the plurality of sand pile units are in one-to-one correspondence with the positions and the plane shapes of a plurality of compartments in the barrel type foundation; positioning deviations are arranged between the outer surface of each sand pile unit and a partition wall in a lower barrel of the barrel type foundation and between the outer surface of the sand pile unit located on the edge of the barrel type foundation and the outer wall of the lower barrel; the barrel type foundation sinks into the soft clay foundation on the seabed surface layer in the mode that the multiple sand pile units are sleeved with the multiple compartments of the lower barrel in a one-to-one correspondence mode till the bottom face of the lower barrel top cover makes contact with the top faces of the multiple sand pile units. The utility model can meet the requirements of bearing capacity and deformation in the use period of the barrel type foundation.

Description

Technical Field

[0001] The utility model relates to a composite foundation structure of a bucket foundation and a full-length sand pile. Background Art

[0002] Concrete bucket foundation (hereinafter referred to as bucket foundation) is a new type of hydraulic structure with an open bottom and a closed top. Its typical structure is as follows: Figure 1a 、 Figure 1b and Figure 1c As shown, the barrel consists of an upper barrel and a lower barrel. The upper barrel is similar to a caisson, while the lower barrel is a topless barrel. Due to the large planar dimensions of a barrel foundation, partition walls are installed inside both the upper and lower barrels to meet the load requirements during construction and operation. The barrel foundation is prefabricated on land and transported to the installation site. Water is pumped to create a pressure differential inside and outside the barrel, overcoming resistance and allowing it to sink. This makes it particularly suitable for soft clay seabeds, offering advantages such as requiring no large equipment for sinking during waterborne construction, shortening waterborne operations, and achieving noise-free construction.

[0003] Currently, bucket foundations are mostly used in water transport projects for breakwaters. When applied to wharf structures, the vertical loads borne by wharf structures are greater than those borne by breakwaters, and they also need to bear the lateral earth pressure caused by the harbor-side fill. Furthermore, settlement control requirements are more stringent, requiring the bucket foundation to penetrate a good bearing layer to a certain depth to meet the bearing capacity and deformation control requirements of the wharf structure during its service life. For the deep, soft clay seabeds prevalent in my country's southeastern coastal areas, using only soft clay as the bearing layer at the bucket end without foundation treatment will not meet the design requirements during its service life. To this end, a research team has proposed using sand piles 2 to treat the deep foundation of the seabed before sinking the bucket foundation 1, forming a deep sand pile composite foundation. By controlling the top elevation of sand piles 2 and the bottom elevation of the bucket foundation, the bucket foundation 1 is sunk to the design elevation and then penetrates a certain depth into the deep sand pile composite foundation, forming a composite structure of bucket foundation and deep sand piles. This allows the bucket foundation to be subjected to combined forces with the deep sand pile composite foundation during its service life (see [1]). Figure 2 ). Figure 2 The figure shows only the ideal situation, that is, the top elevation of the deep sand pile 2 is consistent. In fact, it is very difficult to accurately control the top elevation of the deep sand pile 2 during construction. The top elevation of the deep sand pile 2 is actually discrete, with some being higher than the top elevation of the designed sand pile (i.e., superelevation) and some being lower than the top elevation of the designed sand pile (see Figure 3), super-high sand piles may cause the bucket foundation 1 to enter the deep sand pile composite foundation prematurely, causing subsequent penetration difficulties, and ultimately causing the bucket foundation to be super-high as a whole. This will bring three problems: 1. Penetration difficulties occur before the bucket foundation reaches the design elevation, resulting in reduced construction efficiency; 2. Since the bucket foundation is ultimately super-high, the bottom of the lower bucket cover cannot contact and transmit force with the soil, and additional filling work is required to increase the gap under the lower bucket cover; 3. Since the super-high height of the bucket foundation is caused by the super-high height of local sand piles, the proportion of the bucket foundation that eventually enters the deep sand pile composite foundation is lower than the original design requirements and cannot meet the original design requirements. The bearing capacity and deformation of the foundation need to be verified, and even additional reinforcement treatment may be required. The above problems all bring about the disadvantages of construction delays and increased costs, thus limiting the further promotion and application of bucket foundations and deep sand pile composite foundations. In addition, the detection and subsequent treatment of deep sand pile composite foundations are both difficult. Even if the deep sand piles are found to be too high through detection before the bucket foundation is sunk, there is no particularly effective way to deal with them. Utility Model Content

[0004] The purpose of the utility model is to overcome the defects of the prior art and provide a composite foundation structure of a bucket foundation and a full-length sand pile, which can meet the bearing capacity and deformation requirements of the bucket foundation during its service life.

[0005] The purpose of the utility model is achieved as follows: a composite foundation structure of a bucket foundation and a full-length sand pile, comprising a bucket foundation and a full-length sand pile; the bucket foundation comprises a lower bucket with a lower bucket top cover and an upper barrel fixed on the central axis of the lower bucket top cover, the inner cavity of the lower bucket is divided into a plurality of compartments by arranging a plurality of partition walls; wherein,

[0006] The full-length sand pile is driven into the soft clay foundation on the surface of the seabed, and the top elevation is flush with the seabed surface. The full-length sand pile is divided into a plurality of sand pile units, and the arrangement positions of the plurality of sand pile units correspond one-to-one to the positions of the plurality of compartments in the bucket foundation, and the plane shape of each sand pile unit is adapted to the plane shape of the corresponding compartment. Positioning deviations are set between the outer surface of each sand pile unit and the partition wall in the lower barrel of the bucket foundation, as well as between the outer surface of the sand pile unit located at the edge of the bucket foundation and the outer wall of the lower barrel.

[0007] The bucket foundation is sunk into the soft clay foundation of the seabed surface layer in a manner in which the multiple compartments of the lower bucket are correspondingly sleeved on the multiple sand pile units, until the bottom surface of the lower bucket top cover contacts the top surfaces of the multiple sand pile units.

[0008] In the composite foundation structure of the bucket foundation and the full-length sand piles, the positioning deviation is 0.8 to 1.2 m.

[0009] In the composite foundation structure of the bucket foundation and full-length sand piles, the multiple full-length sand piles constituting each of the sand pile units are arranged in a square.

[0010] The composite foundation structure of the bucket foundation and the full-length sand piles of the utility model has the following characteristics:

[0011] 1. By controlling the layout of the full-length sand piles, the full-length sand piles are prevented from affecting the sinking penetration of the bucket foundation, thus meeting the requirements of the construction period. In addition, the composite structure of the bucket foundation and full-length sand piles has better bearing capacity characteristics during service life, vertical bearing capacity, long-term settlement control, and horizontal anti-slip stability than the composite structure of the bucket foundation and deep sand piles.

[0012] 2. Taking into full consideration the precision and capacity of existing sand pile construction equipment, the rational arrangement of full-length sand piles avoids the difficulty associated with sinking the outer walls and partition walls of the bucket foundation through the sand piles. This maximizes the bucket foundation's advantages of high efficiency during construction and meets the bearing capacity and deformation requirements of the bucket foundation throughout its service life. Furthermore, the construction quality of the composite foundation structure of the bucket foundation and full-length sand piles is easily inspected and addressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1a This is the elevation of the bucket foundation

[0014] Figure 1b yes Figure 1a AA view in the;

[0015] Figure 1c yes Figure 1a BB view in the figure;

[0016] Figure 2 This is an elevation view of the ideal state of the composite foundation structure of bucket foundation and deep sand pile in the prior art;

[0017] Figure 3 This is a vertical view of the actual state of the composite foundation structure of bucket foundation and deep sand pile in the prior art;

[0018] Figure 4 It is an elevation view of the composite foundation structure of the bucket foundation and the full-length sand piles of the utility model;

[0019] Figure 5 yes Figure 4 CC view in the figure;

[0020] Figure 6 This is a plan view of an embodiment of a composite foundation structure of bucket foundation and deep sand piles in the prior art;

[0021] Figure 7 It is a plan view of an embodiment of a composite foundation structure of a bucket foundation and full-length sand piles of the utility model. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings.

[0023] See also Figure 4 and Figure 5 The composite foundation structure of the bucket foundation and the full-length sand pile of the present invention comprises a bucket foundation 1 and a full-length sand pile 2A.

[0024] The barrel foundation 1 includes a lower barrel 11 having a lower barrel top cover 12 and an upper barrel 15 fixed on the central axis of the lower barrel top cover 12. The inner cavity of the lower barrel 11 is divided into multiple compartments 10 by arranging a plurality of partition walls 13.

[0025] The full-length sand piles 2A are driven into the soft clay foundation on the surface of the seabed and the top elevation is level with the seabed surface; the full-length sand piles 2A are divided into multiple sand pile units 20, and the arrangement positions of the multiple sand pile units 20 correspond one-to-one to the positions of the multiple compartments 10 in the bucket foundation 1, and the plane shape of each sand pile unit 20 is adapted to the plane shape of the team camp compartment 10, and the multiple full-length sand piles 2A constituting each sand pile unit 20 are arranged in a square; a positioning deviation is set between the outer surface of each sand pile unit 20 and the partition wall 13 in the lower barrel 11 of the bucket foundation 1, and between the outer surface of the sand pile unit 20 located at the edge of the bucket foundation 1 and the outer wall 14 of the lower barrel, and the positioning deviation is 0.8 to 1.2 m.

[0026] The bucket foundation 1 is sunk into the soft clay foundation of the seabed surface layer in a manner in which the multiple compartments 10 of the lower bucket 11 are correspondingly placed on the multiple sand pile units 20 until the bottom surface of the lower bucket top cover 12 contacts the top surfaces of the multiple sand pile units 20.

[0027] The length and width of the lower barrel 11 of the bucket foundation 1 are 40m and 20m respectively, the thickness of the outer wall 14 of the lower barrel is 400mm, and the lower barrel 11 is divided into fifteen compartments by two partition walls 13 arranged longitudinally and four partition walls 13 arranged transversely. The thickness of the partition wall 13 is 300mm; the diameter of the sand pile is 1200mm.

[0028] If a composite foundation structure of bucket foundation and deep sand piles is adopted, the deep sand piles 2 are arranged evenly in a plum blossom shape, and the center point spacing of the deep sand piles 2 = 1200 / [sqrt(3)×1.05] = 2086.56 mm (see Figure 6 ); the total plane area of ​​bucket foundation 1 is 20×10+20 2 ×π / 4=514.1m 2 ; The replacement rate of equivalent sand piles is 30%.

[0029] If the composite foundation structure of the bucket foundation and the full-length sand pile of the present invention is adopted, the diameter of the sand pile is also 1200mm, and the full-length sand pile 2A is divided into fifteen sand pile units 20 corresponding to the fifteen compartments 10 in the bucket foundation 1. The multiple full-length sand piles 2A constituting each sand pile unit 20 are arranged in a square, and the positioning deviation B between the outer surface of each sand pile unit 20 and the partition wall 13 in the lower bucket 11 and the positioning deviation B between the sand pile unit 20 located at the edge of the bucket foundation 1 and the outer wall 14 of the lower bucket are both set to 1m; the center point spacing of the full-length sand piles 2A in each sand pile unit 20 is empirically calculated to be 1370mm, and a total of 143 full-length sand piles 2A are arranged in the fifteen sand pile units 20 within the range of a single bucket foundation 1 (see Figure 7 ); the total planar area of ​​the full-length sand pile 2A is 143×1.2 2 ×π / 4=161.73m 2 , the replacement rate of equivalent sand piles = 161.73 / 514.16 = 31.4% > 30%, meeting the design requirements.

[0030] Through the above embodiments, the bucket foundation and full-length sand pile composite structure of the utility model can be used to equivalently replace the bucket foundation and deep sand pile composite structure, and the bucket foundation and full-length sand pile composite structure can be used to further carry out targeted optimization design by utilizing the characteristics of better stress resistance during service life.

[0031] The composite foundation structure of bucket foundation and full-length sand piles of the utility model has the following advantages compared with the composite foundation structure of bucket foundation and deep sand piles in the prior art:

[0032] 1. Use full-length sand piles instead of deep sand piles. Since the construction of full-length sand piles is a mature process with a mature quality control system, and subsequent testing is convenient, if quality problems are found, the surface layer can be treated;

[0033] Second, utilizing existing sand piles and construction positioning capabilities, full-length sand piles are installed in the cavity between the outer wall of the lower bucket of the bucket foundation and the partition wall, with a reserved positioning deviation to meet the existing sand pile ship and bucket foundation installation construction accuracy requirements. This ensures that the outer wall and partition wall of the lower bucket of the bucket foundation avoid the sand piles during the sinking process. Bucket foundation sinking construction in soft clay is a mature process with high construction efficiency and controllable construction period.

[0034] Third, the density of full-length sand piles within the layout area can form drainage channels, thereby enhancing the consolidation of the surface soft clay, which is more beneficial to the combined stress and long-term deformation control of the bucket foundation and full-length sand piles during service life;

[0035] Fourth, since the top surface of the full-length sand pile is in full contact with the bottom surface of the lower bucket cover of the bucket foundation, the vertical bearing capacity of the bucket foundation and the full-length sand pile can be effectively improved, meeting the vertical bearing capacity requirements of the wharf structure;

[0036] Fifth, when full-length sand piles are fully embedded in the cavity between the outer wall and the inner partition wall of the bucket foundation, horizontal slippage of the bucket foundation can only occur after the sand pile composite foundation is completely destroyed under horizontal loads such as shore fill pressure and wave forces. The combined foundation structure of a bucket foundation and full-length sand piles can better utilize the sand pile composite foundation, and therefore has a higher horizontal bearing capacity than that of a combined foundation structure of a bucket foundation and deep sand piles. In the latter, the bucket end of the latter can only penetrate the sand pile to a limited depth, and the deep sand piles primarily serve to increase interfacial friction at the bucket end to prevent slippage.

[0037] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the art may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention and should be defined by the claims.

Claims

1. A composite foundation structure of a bucket foundation and a full-length sand pile, comprising a bucket foundation and a full-length sand pile; the bucket foundation comprises a lower bucket having a lower bucket top cover and an upper barrel fixed on the central axis of the lower bucket top cover, and the inner cavity of the lower bucket is divided into a plurality of compartments by arranging a plurality of partition walls; It is characterized in that The full-length sand pile is driven into the soft clay foundation on the surface of the seabed and the top elevation is flush with the seabed surface; the full-length sand pile is divided into a plurality of sand pile units, the arrangement positions of the plurality of sand pile units correspond one to one with the positions of the plurality of compartments in the barrel foundation, and the plane shape of each sand pile unit is adapted to the plane shape of the corresponding compartment; positioning deviations are set between the outer surface of each sand pile unit and the partition wall in the lower barrel of the barrel foundation, and between the outer surface of the sand pile unit located at the edge of the barrel foundation and the outer wall of the lower barrel; The barrel foundation is sunk into the soft clay foundation of the seabed surface layer in a manner that the multiple compartments of the lower barrel are correspondingly sleeved on the multiple sand pile units, until the bottom surface of the lower barrel top cover contacts the top surfaces of the multiple sand pile units.

2. The composite foundation structure of the bucket foundation and the full-length sand pile according to claim 1, It is characterized in that The positioning deviation is 0.8 to 1.2 m.

3. The composite foundation structure of the bucket foundation and the full-length sand pile according to claim 1, It is characterized in that A plurality of full-length sand piles constituting each of the sand pile units are arranged in a square.

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