CN115162394B - Fractional vortex eliminating prevention protection system and vortex eliminating method suitable for pile group foundation - Google Patents
Fractional vortex eliminating prevention protection system and vortex eliminating method suitable for pile group foundation Download PDFInfo
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- CN115162394B CN115162394B CN202210990586.5A CN202210990586A CN115162394B CN 115162394 B CN115162394 B CN 115162394B CN 202210990586 A CN202210990586 A CN 202210990586A CN 115162394 B CN115162394 B CN 115162394B
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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
- E02D27/10—Deep foundations
- E02D27/12—Pile foundations
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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
- E02D27/10—Deep foundations
- E02D27/12—Pile foundations
- E02D27/14—Pile framings, i.e. piles assembled to form the substructure
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D31/00—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution
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Abstract
The invention discloses a fractional vortex eliminating prevention protection system and a vortex eliminating method suitable for pile group foundations, comprising the following steps: a bearing platform vortex eliminating member arranged between the bearing platforms; pile group vortex eliminating members; the pile group vortex eliminating component comprises a sacrificial pile arranged at the front end of a pile group foundation and a vortex eliminating sheet arranged at the front end of a pile group first row of pile foundations or the front end of the sacrificial pile; when a plurality of vortex eliminating sheets are installed, the vortex eliminating sheets are distributed in sequence from top to bottom. The system and the method for preventing and protecting the vortex elimination of the branches suitable for the pile group foundation have the advantages that the structural design is very simple from the scouring mechanism of the pile group foundation, and the water flow power at different parts of the pile group foundation is reduced through the combined action of a plurality of measures, so that the overall vortex intensity of the periphery of the pile group foundation is reduced, and the aim of reducing the local scouring of the pile group foundation is finally achieved; vortex eliminating treatment is carried out on water flows of different parts of the pile groups respectively, so that scouring of pile group foundations can be reduced to the greatest extent; compared with other protective measures, the cost is controllable, and the method has higher economic benefit.
Description
Technical Field
The invention belongs to the technical field of disaster prevention and reduction of bridge foundations, and particularly relates to a subsection vortex eliminating prevention and protection system and a vortex eliminating method suitable for pile group foundations.
Background
The pile group foundation has stronger complex hydrodynamic adaptability, such as tide or wave environment, and becomes one of important foundation forms in river-crossing and sea-crossing bridge construction gradually. The pile group foundation is generally composed of an upper pier, a middle bearing platform and a lower pile group pile foundation, and compared with a single pier foundation, the scouring mechanism is more complex. At present, for the scour protection of pile group foundations of a river-crossing or sea-crossing bridge, two modes are basically adopted: firstly, adopting hard protection measures, throwing and filling materials such as broken stone in a scouring pit formed by pile groups, so that engineering investment is huge, and broken stone has high possibility of water destruction under the action of complex extremely offshore or estuary hydrodynamic environment, and later maintenance cost is huge, so that a second measure called deceleration and folding is often needed. The method mainly aims at protecting pile group foundations by inserting sacrificial piles in different arrangement modes at a certain distance before piers, but the method needs a plurality of sacrificial piles to play a certain protection effect under the combined action, requires great investment, easily causes other negative effects, cannot maximally reduce the overall vortex strength around and in the pile group foundations, cannot effectively reduce the local scouring of the pile group foundations, and therefore, needs to develop a fractional vortex elimination prevention protection system and a vortex elimination method suitable for the pile group foundations to solve the existing problems.
Disclosure of Invention
The invention aims to provide a fractional vortex eliminating prevention protection system and a vortex eliminating method suitable for a pile foundation, which are used for solving the problem that the strength of the whole vortex around the pile foundation cannot be reduced.
In order to achieve the above purpose, the present invention provides the following technical solutions: a system for vortex reduction prevention in a subsection suitable for a pile foundation, comprising:
the bearing platform vortex eliminating component is arranged on the bearing platform upstream side;
pile group vortex eliminating members;
the pile group vortex eliminating component comprises a sacrificial pile arranged at the front end of a pile group foundation and a vortex eliminating sheet arranged at the front end of a pile group first row of pile foundations or the front end of the sacrificial pile; when a plurality of vortex eliminating sheets are installed, the vortex eliminating sheets are distributed in sequence from top to bottom, and are arranged at equal intervals or in a sparse mode from top to bottom, wherein the vortex eliminating sheets at the lowest part are closely attached to a bed surface, slide along with the fluctuation of a mud surface and are attached to the mud surface, and other vortex eliminating sheets are fixedly installed;
the bearing platform vortex eliminating component is arranged on the upstream side of the bearing platform.
Preferably, the bearing platform vortex eliminating member comprises a straight-face bearing platform vortex eliminating member, a cambered-face bearing platform vortex eliminating member or a curved-face bearing platform vortex eliminating member;
preferably, the width b of the vortex eliminating member of the straight surface bearing platform c1 Width b of the bearing platform 2 Same height P c1 The thickness P of the bearing platform is the same, and the length of the straight surface of the triangle is (P 2 +b 2 2 ) 1/2 。
Preferably, a plurality of energy dissipation holes with the radius delta r and the depth delta h are uniformly distributed on the straight surface of the vortex eliminating component of the straight surface bearing platform.
Preferably, the width b of the arc surface bearing platform vortex eliminating component c2 Width b of the bearing platform 2 Same height P c2 And the thickness P of the bearing platform is the same, one side surface is an arc angle curved surface, and the central angle gamma of the arc angle curved surface is smaller than 90 degrees and larger than 45 degrees.
Preferably, the width b of the vortex eliminating member of the curved bearing platform c3 Width b of the bearing platform 2 The same, its height P c3 The thickness P of the bearing platform is the same.
Preferably, the vortex eliminating sheet is a crescent structure attached to a circular pile foundation, the central angle beta of the vortex eliminating sheet ranges from 120 degrees to 180 degrees, the maximum width of the vortex eliminating sheet is delta b, and the radius of the circular arc is r 4 The arc length is beta pi r 4 180, the length of the inner arc line close to the pile foundation is alpha pi r 3 Alpha is the central angle of the corresponding pile foundation; if the anti-vortex plates are arranged at equal intervals at the front end of the pile foundation, the interval between the anti-vortex plates is Z/n, wherein Z is the distance from the bottom of the bearing platform to the mud surface, namely the water outlet length of the pile foundation, and n is the number of the anti-vortex plates (1); if the vortex eliminating sheets are arranged in a dense manner from top to bottom, the distances between the vortex eliminating sheets are delta Z1, delta Z3, … … and delta Zn in sequence from top to bottom; the thickness of the vortex eliminating sheets is delta d, and at least three vortex eliminating sheets are arranged on a single pile foundation.
Preferably, the pile foundation diameter d of the sacrificial pile x Diameter d of pile group 3 The same, its height P x The distance Z from the bottom of the bearing platform to the mud surface is equal to the height P if the pile group has anti-collision requirement x Increase in sizeTo the elevation (P+Z) of the bearing platform, the distance L from the front edge of the bearing platform is 1-2 times the length a of the bearing platform 2 。
The invention also provides a vortex eliminating method of the subsection vortex eliminating prevention protection system suitable for the pile group foundation, which comprises the following steps:
step 1, arranging pile foundations of lower pile groups in an arrangement mode, and when inflow water flows to pile groups, enabling upper i-layer water flow to impact an upper pier to form a vortex S on the top surface of a bearing platform i Due to the length a of the bearing platform 2 Width b 2 Far greater than the diameter d of the pier 1 Vortex S i Cannot spread downwards, is dissipated at the top surface of the bearing platform and is carried downstream by the incoming water flow, and the partial water flow utilizes the length a of the bearing platform 2 Achieve the purpose of eliminating vortex, the length a of the bearing platform 2 The sum of the length P of the vortex eliminating component and the bearing platform is more than or equal to 4 times of pier diameter d 1 Meeting the requirements of vortex elimination of the upper bridge pier;
step 2, forming a diving flow V for the impact bearing platform head-on flow surface of the middle water flow j dj The diving flow V di The front mud surface of the submerged pile foundation is dragged into the pile foundation under the action of lower water flow, and the submerged pile foundation is divided into an upper stream and a lower stream when impacting the curved surface bearing platform vortex eliminating member by taking the curved surface bearing platform vortex eliminating member as an example, and one part of the submerged pile foundation is opposite to vortex S in a U-shaped groove of the curved surface bearing platform vortex eliminating member j The vortex is eliminated, the other part of water flow forms a reflection flow, the direction of the reflection flow is opposite to that of the incoming water flow, a reverse counteracting water flow is formed, and the intensity of the incoming water flow is counteracted;
step 3, for the lower water flow k, after the water flow impacts the sacrificial pile at the front end of the pile foundation of the pile group, forming lower submerged water flow on the corresponding flow facing surface of each pile foundation, forming a plurality of eddies on the periphery of the pile foundation, and forming a vortex system S together k1 The intensity of the incoming water flow is reduced to a certain extent, and then when the water flow is reduced to impact vortex eliminating sheets on the first row of pile foundations of the pile group foundation, a plurality of vortex S are formed between the vortex eliminating sheets k2 Vortex is eliminated between two vortex eliminating sheets, so that no down-flow is formed, the peripheral vortex strength of each pile foundation at the upstream side is weakened, and meanwhile, the sacrificial piles which are arranged in front of the pile foundation and face to the space between the pile groups are required to be emphasizedThe distance arrangement is used for forming choked flow, so that the stream of water is prevented from directly rushing into the arrangement space of the pile groups, and the high-speed water is further compressed to wash the mud surface at the lower part of the foundation.
Preferably, in step 1, the method for arranging the pile foundations of the lower pile group comprises the following steps of,
the pile foundation of the lower pile group adopts a 3X 3 mode, and the distance m is 2 times of the diameter d of the pile 3 The applicable spacing m of the sacrificial piles is 2-4 times of pile diameter.
The invention has the technical effects and advantages that: the system and the method for preventing and protecting the vortex elimination of the branches suitable for the pile group foundation have the advantages that the structural design is very simple from the scouring mechanism of the pile group foundation, and the water flow power at different parts of the pile group foundation is reduced through the combined action of a plurality of measures, so that the overall vortex intensity of the periphery of the pile group foundation is reduced, and the aim of reducing the local scouring of the pile group foundation is finally achieved; vortex eliminating treatment is carried out on water flows of different parts of the pile groups respectively, so that scouring of pile group foundations can be reduced to the greatest extent; compared with other protective measures, the cost is controllable, and the method has higher economic benefit.
Drawings
FIG. 1 is a schematic diagram of a vertical arrangement of preventive care measures for vortex elimination of pile group foundation subdivisions in the invention;
FIG. 2 is a schematic diagram of the mechanism of formation of submerged flow under the pile foundation of the present invention;
FIG. 3 is a schematic view of the vortex eliminating member of the vertical surface bearing platform;
FIG. 4 is a schematic diagram of the vortex eliminating member of the cambered surface bearing platform;
FIG. 5 is a schematic view of the vortex eliminating member of the curved surface bearing platform;
FIG. 6 is a schematic view of a sacrificial pile structure of the pile foundation vortex eliminating member of the present invention;
FIG. 7 is a schematic view of the vortex sheet structure of the pile foundation vortex eliminating member of the present invention, wherein the hatched portion is the vortex sheet;
FIG. 8 is a schematic elevational view of the vortex plate of the present invention after installation;
FIG. 9 is a schematic plan view of the vortex plate of the present invention after installation;
FIG. 10 is a schematic plan layout of a lower pile group vortex eliminating member of the present invention;
fig. 11 is a flow chart of the method of the present invention.
In the figure: 1. vortex eliminating sheet; 2. pile foundation; 3. and sacrificial piles.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention provides a subsection vortex eliminating prevention and protection system suitable for pile group foundations, which is shown in figure 1, and comprises three parts, namely a pile group foundation, a bearing platform vortex eliminating member and a pile group vortex eliminating member; the pile group foundation comprises three parts of piers, a bearing platform and pile groups, wherein the bearing platform vortex eliminating members are connected with the bearing platform by adopting screws and nuts, and the bearing platform vortex eliminating members can be arranged on one side of the bearing platform or on both sides of the bearing platform, depending on the hydraulic environment where the piers are located, such as a tidal current bidirectional environment; the pile group vortex eliminating member is divided into two parts, namely a sacrificial pile 3 and a vortex eliminating sheet 1, wherein the vortex eliminating sheet 1 is arranged at the front end of a pile foundation 2, and the sacrificial pile 3 is arranged at a certain distance in front of the pile group;
as shown in fig. 2, the flow velocity of the incoming water flow before the pile group is generally exponentially distributed along the water depth, when the water depth submerges the pile cap by a certain water depth, that is, the distance (p+z) between the top of the pile cap and the river bed is smaller than the water depth H, where P is the thickness of the pile cap and Z is the distance between the bottom of the pile cap and the river bed, it is required that the water flow of a certain thickness from the water facing side of different parts of the pile group impinges on the part, and at the same time, it is required that Z is greater than 0.5 times the water depth H. From the conservation of momentum and the distribution of the flow velocity of the incoming water flow before pile group, the incoming water flow before pile group can form the submerged water flows V with different sizes at different parts di 、V dj V (V) dk . Wherein, diving flow V di Is usually minimum because the width of the upper bridge pier is smaller and the flow velocity of the upper water flow is developed more sufficiently, so that the flow velocity of the generated lower submerged water flow is smaller, and the part of the lower submerged water flow is usually subjected to the lower bearing platformThe water blocking function of the plane is difficult to submerge and spread to the bed surface so as to influence scouring. Therefore, the bottom surface of the bearing platform is far from the bed surface and the length a of the bearing platform 2 Is the diameter d of the pier diameter of the upper pier 1 When the number is more than 3 times, the influence of the lower submerged flow formed by the upper bridge pier can be ignored; diving flow V dj Generally, the size of the bearing platform is larger, so that the formed lower submerged water flow is often dragged by the inflow water flow at the lower layer of the bearing platform to be brought into the pile group to form high-speed extrusion water flow, thereby playing an important role in starting sediment in the pile foundation 2 and transporting bed sand, and being one of the important reasons for scouring the pile group; diving flow V dk The impact is the greatest, the impact on scour is the greatest, the partial submerged flow is the submerged flow formed on the head-on surface of each pile foundation 2 at the lower part, usually the first row of piles, will cause the scour of each pile foundation 2, meanwhile, because there is a pile spacing gap between the pile foundations 2 and pile foundations 2, besides the water flow impacting the pile foundations 2, taking parallel pile groups as an example, the rest water flow can be extruded and accelerated in the pile groups, and a large amount of silt in the pile groups can be smoothly taken away;
for the situation that the bearing platform is submerged and the bearing platform bottom is far away from the bed bottom or has a certain distance, the influence of the upper pier on scouring is small or almost none, the middle bearing platform is inferior, and the lower pile group foundation is the largest. The technical scheme of the invention needs to be installed in time after bridge construction, because a certain safety depth is reserved in the bridge foundation design to avoid the safety threat to the bridge structure caused by unexpected scouring, the sediment thickness in the pile group is a holding medium for maintaining the foundation safety, and the purpose of pre-protection is to protect the sediment medium from being carried by water flow as much as possible and to transfer out of the pile group range, so that the pile group can still keep a larger safety burial depth even after a certain scouring condition is generated;
the bearing platform vortex eliminating member comprises a straight bearing platform vortex eliminating member structure and a cambered bearing platform vortex eliminating member, and the bearing platform vortex eliminating member is made of a relatively economical light material or a material with a certain energy absorbing effect so as to increase the collision resistance of the bearing platform; for the vortex eliminating component of the straight-face bearing platform, the vertical face of the vortex eliminating component is completely attached to the side face of the bearing platform, and the height P of the vortex eliminating component is as high as c1 The size of the side surface of the bearing platform is consistent, namely the vertical surface height of the vertical surface triangle isP is as follows; the thickness is consistent with the bearing platform thickness, the width b c1 Is equal to the width b of the bearing platform 2 The method comprises the steps of carrying out a first treatment on the surface of the Its length L and upper pier diameter d 1 Length of bearing platform a 2 The relative relationship is a certain relationship, and is generally considered as: a, a 2 4 to 6 days or more 1 And when the upper bridge pier has small or negligible influence on scouring.
The piers are common pile group foundations, and as shown in FIG. 2, the upper piers are generally round piers or square piers, for which the diameter is d 1 Radius r 1 For square piers, the length is a 1 Width b 1 The method comprises the steps of carrying out a first treatment on the surface of the The central bearing platform is generally circular or square, and for a circular bearing platform, the diameter is d 2 Radius r 2 For square bearing platform, the length is a 2 Width b 2 The thickness is P; the pile group is generally cylindrical, the arrangement form is p×l, the pile spacing is m, the arrangement spacing is equal, the arrangement spacing is m, and the diameter is d 3 Radius r 3 In this embodiment, taking round piers, square bearing platforms and cylindrical pile groups as examples, and taking unidirectional flow as examples, implementing subsection vortex eliminating pre-protection, and arranging vortex eliminating members symmetrically during bidirectional flow; in FIG. 2, Δy represents a stratified water flow, and a certain water depth is divided into water flow layers with a certain thickness, wherein the water flow is divided into an upper layer i, a middle layer j and a lower layer k, for example, j layers have a water flow velocity u j The corresponding three-layer water flow acts on the pile foundations of the pier, the bearing platform and the lower pile group, and the lower submerged water flow formed by the corresponding three-layer water flow is V respectively di 、V dj 、V dk ；
The structure of the vortex eliminating member of the straight-face bearing platform is a straight-face triangle structure, and the width b of the vortex eliminating member is as shown in figure 3 c1 Width b of the bearing platform 2 Maintain uniform height P c1 The thickness P of the bearing platform is consistent, and the length of the straight surface of the corresponding triangle body is (P 2 +b 2 2 ) 1/2 The device is arranged on the upstream side of the bearing platform, can play a role in lifting and diffusing the water flow of the bearing platform, and meanwhile, the device needs to emphasize that in order to further dissipate the water flow on the straight surface of the triangular body, a certain number of energy dissipation holes with the radius of Deltar and the depth of Deltah are uniformly distributed on the straight surface of the triangular body;
the second is a vortex eliminating component of the cambered surface bearing platform, which is of a curved surface triangle structure, as shown in the figure4. Width b of arc bearing platform vortex eliminating member c2 Width b of the bearing platform 2 Maintain uniform height P c2 The thickness P of the circular arc angle curved surface is consistent with that of the bearing platform, but is different from a straight triangular body structure, the side surface of the circular arc angle curved surface is a certain circular arc angle curved surface, and the circular arc angle curved surface is primarily considered to have a central angle gamma which is not more than 90 degrees and not less than 45 degrees, namely the curved surface is not too concave or too slow, and water flow climbing is not influenced. Meanwhile, the design form can form a reflection flow backwards to offset the water flow intensity of the impact bearing platform, so that the water flow of the bearing platform is prevented from forming a submerged water flow;
the bearing platform vortex eliminating member also comprises a third curved surface bearing platform vortex eliminating member which is of a concave curved surface U-shaped body structure, as shown in figure 5. Width b of vortex eliminating member of curved bearing platform c3 Width b of the bearing platform 2 Maintain uniform height P c3 The thickness P of the pile cap is consistent with the thickness P of the pile cap, namely a U-shaped part is dug out on the flow-facing surface of a rectangular square block, so that the flow-facing water is consumed in the vortex eliminating member of the curved surface pile cap, reflected water is formed to counteract the flow strength of the flow-facing water, the radian and the depth of the flow-facing water can be designed according to actual conditions, the damage of the submerged water under the pile cap to the pile-group flushing protection is usually ignored, and the existing actual conditions are that the influence of the flow-facing water on the flushing is equivalent to that of the pile-group foundation at the lower part, but almost no related design is used for carrying out related protection design on the flushing influence of the pile cap. The bearing platform vortex eliminating member mainly aims at eliminating upper water flow and basically does not form lower submerged flow, the conventional vortex eliminating structure mainly eliminates lower water flow and still generates lower submerged flow with a certain flow velocity to impact a bed surface, meanwhile, the bearing platform vortex eliminating member can form reflected water flow, almost completely avoids the formation of lower submerged flow and can counteract the incoming water flow of the layer, the upper layer forms a larger part of water flow layer with smaller flow velocity, thus the thickness of a boundary layer of the incoming water flow is reduced, the size of the incoming flow velocity is greatly weakened, and the effect which cannot be achieved by other buffer measures or designs is achieved;
the pile group vortex eliminating member consists of two parts, one is a plurality of groups of vortex eliminating sheets 1 arranged at the front end of the first row of pile foundations 2 at the upstream side, as shown in fig. 7, and the other is a sacrificial pile 3 arranged in front of the pile group spacing by a certain distance, as shown in fig. 6. For installation ofThe multiple groups of vortex eliminating sheets 1 are sequentially arranged on the forward end of the first row of pile foundations 2 on the upstream side, the vortex eliminating sheets 1 are crescent sheets attached to the circular pile foundations 2, the central angle beta can be 120-180 degrees, the vortex eliminating sheets are mainly ensured to have a certain maximum width delta b, and the corresponding arc radius is r 4 Its arc length is beta pi r 4 180, the length of the inner arc line close to the pile foundation 2 is alpha pi r 3 The alpha is the central angle of the corresponding pile foundation 2, the distance between the vortex eliminating sheets 1 arranged at the front end of the pile foundation 2 is Z/n, the thickness of the vortex eliminating sheets 1 is Deltad, in the embodiment, the number of the vortex eliminating sheets 1 arranged on the single pile foundation 2 is not less than three, the maximum width Deltab of the crescent thin sheet can be obtained through calculation of circumference and triangle theorem, wherein Z is the distance from the bottom of a bearing platform to the mud surface, the water outlet length of the pile foundation 2 is also the number of the vortex eliminating sheets (1);
for the second part of the sacrificial pile 3, which is mainly to block the extruded water flow entering the range of pile group spacing, the diameter d of the pile foundation 2 of the sacrificial pile 3 x Diameter d of pile group 3 Maintain uniform height P x The distance Z from the bottom of the bearing platform to the mud surface is equal to the height P if the pile group foundation has anti-collision requirement x The height of the bearing platform is increased to the height (P+Z), and the distance L between the height and the front edge of the bearing platform is 1 to 2 times of the length a of the bearing platform 2 It is emphasized that the vortex eliminating sheet 1 in the pile group vortex eliminating member is different from a common guard ring structure, and the crescent vortex eliminating sheet 1 is attached to the pile foundation 2, so that any influence on water flow around the pile foundation 2 is hardly generated. The first vortex eliminating sheet 1 at the lowest part is arranged close to the bed surface, the vortex eliminating sheet 1 can slide along with the change of the mud surface, the vortex eliminating sheet is attached to the mud surface at any time, and other vortex eliminating sheets 1 at the upper parts are fixed. The guard ring structure is usually arranged near the mud surface, and once the mud surface is exposed, the guard effect is ineffective, the applicability is poor, meanwhile, the multi-stage vortex eliminating sheet 1 not only can prevent the formation of the submerged water flow, but also can form vortex eliminating grooves and certain reflection flows between the submerged water flow and the vortex eliminating grooves, so that the strength of the incoming water flow and the peripheral vortex of the pile foundation 2 is greatly weakened, which is incomparable with the common guard ring structure, and the manufacturing cost is lower. It should be emphasized that the present invention provides a smaller number of sacrificial piles 3 than other pre-pier sacrificial pile 3 arrangements without the need for a large cost Zhou Zhangbu to be placed throughout the pile groupIn the range, the sacrificial piles 3 are arranged to mainly aim at pile-passing water flow of pile group spacing, the form is quite simple, the influence on peripheral scouring and bed surface evolution of the sacrificial piles is minimum, and an anti-collision effect can be achieved. From the economical point of view, even if the arrangement failure of the sacrificial pile 3 is avoided, the excessive cost is not paid for repairing, the repairing space is greatly improved, and meanwhile, the scouring can be greatly reduced only for the bearing platform vortex eliminating member and the vortex eliminating sheet 1, which is the advantage and function which are not provided by the arrangement of other sacrificial piles 3;
as shown in fig. 8, vortex sheets 1 are sequentially installed at the front end of each pile foundation 2 of the first row of pile groups or at the front end of a sacrificial pile 3 before piers at certain intervals, wherein fig. 8 is a vertical layout design of a plurality of pile foundation vortex eliminating members installed at the front ends of the pile foundations 2 of the first row of pile groups, and fig. 9 is a basic plane layout of a single pile foundation 2;
as shown in fig. 1 and 10, the vortex eliminating members are installed or arranged on the pile foundation to form a protection system suitable for the vortex eliminating of the branches of the pile foundation. Wherein fig. 1 is a schematic vertical arrangement view of preventive care measures for vortex elimination of pile group foundation subsection, and fig. 10 is a schematic plan arrangement view of a lower pile vortex elimination member.
As shown in FIG. 11, a vortex eliminating method suitable for a distributed vortex eliminating prevention and protection system of pile group foundations is exemplified by unidirectional flow, the pile foundations 2 of the lower pile group are arranged in a 3×3 arrangement mode, and the distance m is 2 times of the pile diameter d 3 It should be noted that, the pile diameter of the sacrificial pile 3 of the present invention with the applicable spacing m of 2-4 times is also related to the distance L from the bearing platform, and the specific situation can be specifically arranged according to the specific process, as shown in FIG. 1, when the incoming water flows to the pile group foundation, the upper i-layer water flow impacts the upper pier, and a vortex S is formed on the top surface of the bearing platform i Due to the length a of the bearing platform 2 Width b 2 Is usually far larger than the pier diameter d of the pier 1 Vortex S i The water flow is difficult to diffuse downwards, is directly dissipated at the top surface of the bearing platform and is carried to the downstream by the incoming water flow, and the vortex eliminating purpose can be achieved by utilizing the certain length of the bearing platform. The invention preliminarily considers that the length a of the bearing platform 2 The sum of the length P of the vortex eliminating component and the bearing platform is more than or equal to 4 times of pier diameter d 1 Can meet the requirement of vortex elimination of the pier at the upper partIs not limited; for the middle-layer water flow j, the part of water flow is assumed to impact the head-on flow surface of the bearing platform, and is known according to the momentum conservation and flow velocity distribution rule, so as to form a lower submerged flow V dj The submerged water flow can be submerged to directly act on the front mud surface of the pile group foundation, and can also be dragged into the pile group foundation under the action of the water flow at the lower layer of the submerged water flow, so that the submerged water flow is extruded and accelerated by the interior of the pile group foundation and washes out sediment in the pile group foundation. When the bearing platform vortex eliminating member is installed, in this embodiment, the curved bearing platform vortex eliminating member is taken as an example, the water flow impacting the head-on surface of the bearing platform is divided into two parts up and down, and the vortex S is mainly opposite to the vortex except that a certain vortex eliminating exists in the curved bearing platform vortex eliminating member j The vortex is eliminated, most water flows form reflection flows, the direction of the reflection flows is approximately opposite to that of incoming water flows, the strength of the incoming water flows is counteracted, and the installation of the bearing platform vortex eliminating component not only avoids the formation of submerged water flows, but also forms reverse counteraction water flows, so that the influence of the bearing platform water flows on flushing is greatly weakened; for the lower water flow k, before the lower pile group vortex eliminating component combination is not installed, the scouring condition is very complex due to the existence of the lower pile group foundation, after the water flow impacts each pile foundation 2 foundation, the lower submerged water flow is formed on the upstream surface of each pile foundation 2, a plurality of vortices are formed around the pile foundation 2 to absorb sediment around the single pile foundation 2, the scouring degree of the rear pile foundation 2 is obviously smaller due to the covering effect of the previous pile foundation 2, only less sediment is carried away by the water flow, but the pile foundation 2 interval gap between each column of the pile foundations 2 is formed, the water flow is extruded and accelerated in the gap to form high-speed water flow due to the influence of the choking of any pile foundation 2, a certain scouring pit is formed between intervals, and then under the influence of the tracing scouring, the scouring pit of the single pile foundation 2 is expanded to the whole pile foundation 2, the sediment inside the whole pile foundation 2 is gradually scoured by the covering effect, and is transported to a certain range outside the pile foundation 2 by the complex turbulence structure and the high-speed water flow, and a certain threat is generated to the safety of the pile pier. After the lower vortex eliminating component is installed, firstly, the incoming water flow impacts the foundation of the sacrificial pile 3 before the pier, and due to the water blocking effect, the strength of the incoming water flow is weakened, and a plurality of vortices S are formed before the pier k1 And also follow the water flow to bring part of the sediment into or near the downstream pile group foundation. Then the water flow continuously impacts each pile foundation 2 of the downstream pile group foundation, a plurality of vortex eliminating sheets 1 are sequentially arranged on each pile foundation 2 of the first row of pile group foundation, the water flow impacts the pile foundation 2 after the water flow passes through the layers, and a plurality of vortex S are formed among the vortex eliminating sheets 1 k2 The vortex is eliminated between the two vortex eliminating sheets 1, and the formation of a down-flow is difficult, so that the strength of the peripheral vortex of the foundation 2 of each pile foundation on the upstream side is greatly weakened. It is emphasized that the installation of sacrificial piles 3 in front of the pile group foundation, which are arranged just opposite the spacing between the pile groups, creates a choked flow, avoiding that this flow of water rushes directly into the interior of the pile group spacing. The lower vortex eliminating member combined by the sacrificial pile 3 and the vortex eliminating sheet 1 before the pile jointly damages or eliminates the vortex of lower water flow, so that the scouring influence of the water flow on sediment in the lower water flow is reduced to the maximum extent;
aiming at pile-group pier foundations, the influence mechanism of different parts of pile groups on scouring is utilized, water flow or vortex formed by each part is effectively killed, the purpose of smaller scouring is achieved more scientifically and effectively, the design is relatively simple, the bearing platform vortex eliminating member and the vortex eliminating sheet 1 are extremely low in production cost, a certain anti-collision function can be achieved, compared with the prior arrangement mode that a plurality of sacrificial piles 3 are arranged in the whole pile-group range, a great amount of cost investment can be saved, the evolution and scouring influence of the peripheral bed surface is less influenced, and the bearing platform vortex eliminating member and the vortex eliminating sheet 1 have better economic benefit and social benefit and can be considered as anti-collision piers to a certain extent.
Finally, it should be noted that: the foregoing description is only illustrative of the preferred embodiments of the present invention, and although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described, or equivalents may be substituted for elements thereof, and any modifications, equivalents, improvements or changes may be made without departing from the spirit and principles of the present invention.
Claims (9)
1. A vortex eliminating method of a subsection vortex eliminating prevention protection system suitable for pile group foundations is characterized by comprising the following steps of: the system comprises:
a bearing platform vortex eliminating member arranged between the bearing platforms;
pile group vortex eliminating members;
the pile group vortex eliminating component comprises a sacrificial pile (3) arranged at the front end of a pile group foundation (2) and a vortex eliminating sheet (1) arranged at the front end of a pile group first row of pile foundations (2) or the front end of the sacrificial pile (3); when a plurality of vortex eliminating sheets (1) are installed, the vortex eliminating sheets are distributed from top to bottom in sequence, are arranged at equal intervals or are distributed at intervals from top to bottom, the vortex eliminating sheet (1) at the lowest part is closely attached to the bed surface, the vortex eliminating sheet (1) slides along with the change of the mud surface and is attached to the mud surface, and other vortex eliminating sheets (1) are fixedly installed;
the bearing platform vortex eliminating component is arranged on the upstream side of the bearing platform; the method comprises the following steps:
step 1, arranging a lower pile group pile foundation (2), and when the inflow water flows to the pile group foundation, the upper i-layer water flow impacts the upper pier to form a vortex S on the top surface of the bearing platform i Due to the length a of the bearing platform 2 Width b 2 Far greater than the diameter d of the pier 1 Vortex S i Cannot spread downwards, is dissipated at the top surface of the bearing platform and is carried downstream by the incoming water flow, and the partial water flow utilizes the length a of the bearing platform 2 Achieve the purpose of eliminating vortex, the length a of the bearing platform 2 The sum of the length P of the vortex eliminating component and the bearing platform is more than or equal to 4 times of pier diameter d 1 Meeting the requirements of vortex elimination of the upper bridge pier;
step 2, forming a diving flow V for the impact bearing platform head-on flow surface of the middle water flow j dj The diving flow V di The front mud surface of the submerged pile foundation is dragged into the pile foundation under the action of lower water flow, and is divided into an upper stream and a lower stream when being a vortex eliminating component of the curved surface bearing platform, and one part of the mud surface is opposite to the vortex S in the U-shaped groove of the vortex eliminating component of the curved surface bearing platform j The vortex is eliminated, the other part of water flow forms a reflection flow, the direction of the reflection flow is opposite to that of the incoming water flow, a reverse counteracting water flow is formed, and the intensity of the incoming water flow is counteracted;
step 3, for the lower water flow k, after the water flow impacts the sacrificial pile (3) at the front end of the pile group pile foundation (2), the water flow is in phase with the sacrificial pileThe head-on flow surface of each pile foundation (2) forms a lower submerged flow, and forms a plurality of eddies around the pile foundation (2) to jointly form an eddy system S k1 The intensity of the incoming water flow is reduced to a certain extent, and then when the water flow is reduced to impact the vortex eliminating sheets (1) on the first row of pile foundations (2) of the pile group foundation, a plurality of vortex S are formed between the vortex eliminating sheets (1) k2 Vortex is eliminated between the two vortex eliminating sheets (1), and a down-submerged flow cannot be formed, so that the strength of the peripheral vortex of the foundation (2) of each pile foundation on the upstream side is weakened; it is emphasized that the sacrificial piles (3) arranged in front of the pile group foundation are arranged opposite to the pile group spacing to form choked flow, so that the water flow is prevented from directly rushing into the pile group arrangement spacing, and the water flow is further compressed to generate high-speed water flow to scour the lower mud surface of the foundation.
2. The method according to claim 1, characterized in that: the bearing platform vortex eliminating component comprises a straight-face bearing platform vortex eliminating component, a cambered-face bearing platform vortex eliminating component or a curved-face bearing platform vortex eliminating component.
3. The method according to claim 2, characterized in that: width b of the vortex eliminating member of the straight surface bearing platform c1 Width b of the bearing platform 2 Same height P c1 The thickness P of the bearing platform is the same, and the length of the straight surface of the triangle is (P 2 +b 2 2 ) 1/2 。
4. A method according to claim 3, characterized in that: and a plurality of energy dissipation holes with the radius of Deltar and the depth of Deltah are uniformly distributed on the straight surface of the vortex elimination component of the straight surface bearing platform.
5. The method according to claim 2, characterized in that: width b of the arc surface bearing platform vortex eliminating component c2 Width b of the bearing platform 2 Same height P c2 And the thickness P of the bearing platform is the same, one side surface is an arc angle curved surface, and the central angle gamma of the arc angle curved surface is smaller than 90 degrees and larger than 45 degrees.
6. A method according to claim 2, characterized in that: width b of the vortex eliminating member of the curved surface bearing platform c3 Width b of the bearing platform 2 The same, its height P c3 The thickness P of the bearing platform is the same.
7. The method according to claim 1, characterized in that: the vortex eliminating sheet (1) is of a crescent structure attached to the circular pile foundation (2), the central angle beta of the vortex eliminating sheet (1) ranges from 120 degrees to 180 degrees, the maximum width of the vortex eliminating sheet is delta b, and the radius of an arc is r 4 The arc length is beta pi r 4 180, the length of the inner arc line close to the pile foundation (2) is alpha pi r 3 Alpha is the central angle of the corresponding pile foundation (2); if the vortex eliminating sheets are arranged at the front end of the pile foundation (2) at equal intervals, the interval between the vortex eliminating sheets (1) is Z/n, wherein Z is the distance from the bottom of the bearing platform to the mud surface, namely the water outlet length of the pile foundation (2), and n is the number of the vortex eliminating sheets (1); if the vortex eliminating sheets (1) are arranged in a dense manner from top to bottom, the distances between the vortex eliminating sheets are delta Z1, delta Z3, … … and delta Zn in sequence from top to bottom; the thickness of the vortex eliminating sheets (1) is delta d, and at least three vortex eliminating sheets (1) are arranged on a single pile foundation (2).
8. The method according to claim 1, characterized in that: diameter d of pile foundation (2) of sacrificial pile (3) x Diameter d of pile group 3 The same, its height P x The distance Z from the bottom of the bearing platform to the mud surface is equal to the height P if the pile group has anti-collision requirement x The height of the bearing platform is increased to the height (P+Z), and the distance L between the height and the front edge of the bearing platform is 1 to 2 times of the length a of the bearing platform 2 。
9. The method according to claim 1, characterized in that: in step 1, the method for arranging the lower pile group pile foundation (2) comprises the following steps:
the pile foundation (2) of the lower pile group adopts a 3 multiplied by 3 form, and the spacing m is 2 times of the diameter d of the pile 3 The sacrificial piles (3) are applicable to pile diameters with a spacing m of 2-4 times.
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| CN202210990586.5A CN115162394B (en) | 2022-08-18 | 2022-08-18 | Fractional vortex eliminating prevention protection system and vortex eliminating method suitable for pile group foundation |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104213586A (en) * | 2014-09-18 | 2014-12-17 | 东南大学 | Pile foundation scour protection measure method |
| CN108086138A (en) * | 2017-11-24 | 2018-05-29 | 中国船舶科学研究中心（中国船舶重工集团公司第七0二研究所） | It is a kind of to prevent device of the bridge pier by current erosion |
| CN108442326A (en) * | 2018-05-22 | 2018-08-24 | 同济大学 | A kind of means of defence sacrificed pile group and combine resistance pier footing local scour with river bottom protection jackstone |
| KR101967578B1 (en) * | 2018-06-20 | 2019-04-09 | (주)교하엔텍 | Defensive equipment for pier foundation of scour suppress type |
| CN212077857U (en) * | 2020-01-17 | 2020-12-04 | 华北水利水电大学 | Adjustable vortex-eliminating rectifying device |
-
2022
- 2022-08-18 CN CN202210990586.5A patent/CN115162394B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104213586A (en) * | 2014-09-18 | 2014-12-17 | 东南大学 | Pile foundation scour protection measure method |
| CN108086138A (en) * | 2017-11-24 | 2018-05-29 | 中国船舶科学研究中心（中国船舶重工集团公司第七0二研究所） | It is a kind of to prevent device of the bridge pier by current erosion |
| CN108442326A (en) * | 2018-05-22 | 2018-08-24 | 同济大学 | A kind of means of defence sacrificed pile group and combine resistance pier footing local scour with river bottom protection jackstone |
| KR101967578B1 (en) * | 2018-06-20 | 2019-04-09 | (주)교하엔텍 | Defensive equipment for pier foundation of scour suppress type |
| CN212077857U (en) * | 2020-01-17 | 2020-12-04 | 华北水利水电大学 | Adjustable vortex-eliminating rectifying device |
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