CN114658018A - Water lowering and draining method combining water conservancy project foundation pit and pipe well with light well point - Google Patents
Water lowering and draining method combining water conservancy project foundation pit and pipe well with light well point Download PDFInfo
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Abstract
The invention provides a water conservancy project foundation pit pipe well combined light well point water lowering and draining method, which belongs to the technical field of water conservancy projects, and is characterized in that a water flow supply function is established by considering water-resisting boundary conditions around a foundation pit, a plurality of light well points are virtually arranged on the periphery of the foundation pit, and a water flow loss function is established; combining the water flow supply function and the water flow loss function into a complete calculation function of the water flow relation between the inside and the outside of the pit; calculating the number of light well points needing to be arranged through a complete calculation function; calculating the deepest water level depth of the foundation pit and the embedding depth of a suction well point of the foundation pit through a seepage flow field function; calculating the number of the pumping well points of the foundation pit based on the total water inflow; and performing dewatering and drainage system construction according to the number of the light well points, the number of the pumping well points and the embedding depth of the pumping well points, so that the dewatering and drainage construction scheme of the hydraulic engineering meets the requirement of an optimization target.
Description
Technical Field
The invention relates to a hydraulic engineering foundation pit and pipe well combined light well point dewatering and drainage method, and belongs to the technical field of hydraulic engineering.
Background
In the foundation pit construction, the underground water problem troubles broad students and constructors for a long time, and becomes a great obstacle in engineering construction. In some areas with high underground water level, the earth excavation leads to the fracture of aquifers, and a large amount of underground water inevitably flows into a foundation pit due to the action of pressure difference. If the water lowering and draining work is not carried out in time, the continuous water seepage of the foundation pit causes the deterioration of site construction conditions and the reduction of the bearing capacity of the foundation, and even causes dangerous situations such as piping, quicksand, slope instability and the like. In the foundation engineering with more underground excavation sections and insufficient precipitation, the schedule and the safety of underground excavation construction are probably directly influenced by the side wall retention water; and to the open cut section that does not have fertile groove and effective waterproof material between supporting construction and the major structure, the requirement of precipitation effect is equally stricter. The construction of the deep foundation pit is different from other excavation projects, on one hand, most foundation projects are below the underground water level, and have multiple points, wide areas and long construction periods; on the other hand, most of foundation construction is in a busy area, the influence of forest establishment of surrounding high buildings and the intensive underground pipelines is considered, the relation between the foundation construction and land and traffic must be well handled in the construction, the settlement of surrounding buildings and roads is closely concerned, and the safety of various underground pipelines is ensured. In addition, for projects with large precipitation area and long precipitation time, the influence of the projects on underground water resources and the surrounding environment is also analyzed systematically, and an effective prevention and control plan is made. Therefore, deep foundation pit engineering dewatering is a system engineering closely related to engineering quality, progress and safety, the dewatering effect is important to foundation pit construction safety, and careful treatment and effective dewatering and drainage measures need to be taken.
The light well point dewatering technology is simple, effective and important for dewatering engineering. In the construction of high-rise buildings, municipal works, port hydraulic works or special works, foundation pits with small areas and low water levels are frequently encountered, and the application of light well point technology is common. With the development of modern urbanization, construction sites are narrower due to high-rise buildings in all places, and the precipitation work of foundation pits is particularly critical. The light well point dewatering method is easy to operate, has the characteristics of small space and is just in line with the development trend, high-efficiency and low-cost dewatering is realized, meanwhile, the engineering quality, the progress and the safety are ensured, and the method is one of the most popular dewatering technologies in a plurality of foundation pit dewatering methods.
The light well point dewatering method is divided into a first-stage light well point, a second-stage light well point and a multi-stage light well point, and is one of the most popular dewatering methods in China at present. The light well-point dewatering technology is based on a vacuum principle, underground water and air in a soil body are mixed into liquid, the mixed liquid is pumped into a water-gas separator through a pipeline by using a vacuum pump, then the mixed liquid is separated through a centrifugal pump, the underground water and the air are respectively discharged out of a pipeline system, and finally the purpose of reducing the underground water level is achieved. The light well point dewatering method has smaller well point distance, changes the flow direction of underground water by virtue of the vacuum pressure of the light well point dewatering method, and effectively prevents the underground water from flowing into a foundation pit; meanwhile, underground residual stagnant water can be reduced to the maximum extent, and the stability of soil between the side slope and the pile is ensured.
For example, patent document CN 201811601545.2 proposes a method for combining a water conservancy project foundation pit and a pipe well with a light well point for lowering and draining water, which includes collecting foundation pit geological data, classifying and summarizing the obtained data, and drawing a data statistical list and a foundation pit construction position geological profile; designing a layout scheme of a checking pipe well, and reversely calculating a bottom water surface line according to the determined well arrangement position according to the fact that the top surface of a precipitation curve of a water level falling funnel area is required to be 1.0m lower than the base elevation, so that the bottom water surface line elevation can be obtained; and (4) checking the water yield of the pipe well and performing pipe well construction operation, connecting the main pipe and the pumping system after completing light well point construction, performing trial pumping, and checking the pumping effect. However, although the construction amount of the drainage construction operation is simplified, the efficiency and quality of the foundation pit construction operation still need to be improved.
For example, patent document CN201310068635.0 proposes a method for lowering water level in a pipe well for foundation pit construction, in which a row of pipe wells are arranged along the periphery of the foundation pit 1.5m away from the outer edge of the foundation pit, 3 wells are arranged on each of the left and right sides of the foundation pit, and the number of the arranged pipe wells is increased or decreased according to the effect of water level lowering. The distance between the center of the well and the side line of the building is 1.5m, the distance between the wells is 7m, the diameter of the well mouth is 600mm, the well pipes are installed in sections and are dismantled section by section along with the excavation of the foundation pit to be 30cm above the excavation surface, and the elevation of the normal water level in the well is controlled to be below 48.0m during the construction of the structure so as to ensure that the underground water level of the soil body is lower than the bottom surface of the foundation pit by 0.5 m. The construction procedure is as follows: well position lofting → making well head, safety protection cylinder → drilling machine in place, drilling hole → backfilling well bottom sand cushion → hanging well casing → filtering layer between backfilling pipe wall and hole wall → installing water pumping control circuit → trying to pump → precipitation well working normally, the purpose is to adopt and carry on the foundation construction in the higher area of ground water level, reduce the ground water level, offer a dry operation environment for the foundation structure construction. However, the technical scheme is that the design and construction of the foundation pit support structure are more and more complex along with the deeper excavation and the larger area of the foundation pit, and a construction unit does not have enough technical strength to solve the problems of complex foundation pit stability, deformation and environmental protection.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for lowering and draining water by combining a water conservancy engineering foundation pit and a pipe well with a light well point, which comprises the following steps:
establishing a water flow replenishment function by considering the water-resisting boundary conditions around the foundation pit;
virtually arranging a plurality of light well points on the periphery of the foundation pit, and establishing a water flow loss function;
the water flow supply function and the water flow loss function are combined to form a complete calculation function of water flow relation inside and outside the pit;
calculating the number of the light well points needing to be arranged through the complete calculation function;
calculating the deepest water level depth of the foundation pit and the embedding depth of a suction well point of the foundation pit through a seepage flow field function;
calculating the number of the pumping well points of the foundation pit based on the total water inflow;
and performing drainage system construction according to the number of the light well points, the number of the pumping well points and the burying depth of the pumping well points.
Further, the water flow replenishment function is:
the water flow loss function is:
in the formula, h is the water level of a node with coordinates (x, y) at the moment t; q (t) is the average water flow supply received by the unit area in the pit at the time t; b is the bottom plate elevation of the aquifer at the coordinate (x, y); n is the number of light well points, W is the number of pumping well points, kx、kyPermeability coefficients in x and y directions; x is the number ofw、ywCoordinates of the pumping well point; qwIn order to pump the well point flow rate,
is a singular function; q. q.sNPumping volume for a single light well point, xN、yNAnd the coordinates of the light well points.
Further, when precipitation starts, q (t) is equal to zero, solving a water flow replenishment function to obtain the water level of each node in the pit at the end of the first period, and meanwhile, the initial water level of each node outside the pit is known;
averaging the water levels of all nodes in the pit to obtain an average water level hm; calculating the average value of the water levels of the nodes outside the pit to obtain an average water level Hm;
calculating the average water flow replenishment quantity q of the outside of the pit to the inside of the pit in a unit area:
q=b（Hm–hm）/(d1+2d2) ；
b is d1、d2Weighted average value of vertical permeability coefficient of soil body in the range;
solving a water flow supply function according to the average water flow supply quantity q to obtain the water level value of each node in the pit at the end of the next period;
let q' = qA; wherein A is the side area of the foundation pit, and q' is the light periphery of the foundation pitThe sum of the pumping quantities of the well points leads to the q in the water flow loss functionN= q'/N, where N is the number of extra-pit light well points; solving a water flow loss function to obtain the water level of each node outside the pit at the end of the next period;
the above calculation process is repeated until the end of the calculation period.
Further, the step of calculating the deepest water level depth of the foundation pit and the embedding depth of the suction well point of the foundation pit through the seepage flow field function comprises the following steps:
z is the height of a flow field at the position x away from the pumping well point, the average flow velocity v = k multiplied by dz/dx of the water seepage section is calculated, k is the permeability coefficient, the side area of the foundation pit is A,
；
water yield of the water seepage section:
，
separate variables, integrate on both sides:
taking the boundary conditions x = R and z = H to obtain:
substituting C to obtain a seepage flow field function:
according to the water level depth z, taking the deepest water level depth zm，
The embedding depth H is more than or equal to zm。
Further, according to the total water inflow quantity Q, setting a utilization coefficient to be 1.1, and calculating the number W =1.1Q/p of the pumping well points; p is the tube well suction for a single suction well point.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.
FIG. 1 is a schematic view of a top view structure of the foundation pit tube well combined with a light well point model.
Fig. 2 is a schematic cross-sectional view of the foundation pit tube well in combination with a light well site model of the present invention.
FIG. 3 is a flow chart of a method for lowering and draining water by combining a hydraulic engineering foundation pit, a pipe well and a light well point.
Fig. 4 is a schematic top view of a foundation pit and tube well combined light well point model according to another embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
On the premise of meeting the construction requirements of the foundation pit pipe well, the surrounding conditions of the foundation pit pipe well and the water flow relation inside and outside the foundation pit are considered, a series of dewatering well points are virtually arranged on the periphery of the foundation pit for the water flow supply quantity received outside and inside the pit, and an optimization design is made, so that the dewatering and drainage construction scheme of the hydraulic engineering meets the requirements of an optimization target.
As shown in fig. 1, which is a schematic view of a top view structure of the foundation pit pipe well system of the present invention, the foundation pit pipe well system is divided into an inner pit portion and an outer pit portion, the inner pit portion and the outer pit portion are separated by a foundation pit protective structure, the periphery of the foundation pit protective structure is virtually provided with a plurality of light well points, and the inner ring of the foundation pit protective structure is provided with a plurality of pumping well points.
After the foundation pit pipe well system is excavated, the aquifer is cut off, the balance of underground water is damaged, the water pressure difference exists between the water surface of the underground water and the bottom surface of the foundation pit, water seepage is generated, the flow track of water flow forms a flow field, meanwhile, the soil body generates resistance to water due to the flow of the underground water in the soil, and the water generates counter-force, namely osmotic pressure, to the soil.
In order to ensure the normal operation of construction, prevent the collapse of the side slope of a foundation pit pipe well system and the reduction of the bearing capacity of the foundation pit, and overcome the adverse effects of underground water such as quicksand, piping, bottom gushing and the like, the design of foundation pit dewatering and drainage is required.
Firstly, considering the water flow connection between the inside and the outside of the foundation pit, respectively carrying out plane finite element analysis inside and outside the pit, and connecting the two parts by the water flow from the outside of the pit to the inside of the pit.
The finite element analysis is based on a subdivision discretization and block interpolation method, a continuously solved area is discretized into a group of finite element assemblies which are mutually connected together according to a certain mode, and an approximate function assumed in each element is utilized to represent unknown field functions to be solved on a fully solved area in a slicing mode. The approximation function within a cell is expressed by the values of the unknown field function or its derivatives at the various nodes of the cell and its interpolation function.
The values of the unknown field functions or derivatives thereof on each node become new unknown quantities, the unknown quantities are solved, and the approximate values of the field functions in each unit are calculated through interpolation functions, so that the approximate solution on the whole solution domain is obtained.
As the number of elements increases, the approximation of the solution will continually improve, and if the elements are such that they meet the convergence requirement, the approximated solution will eventually converge to the exact solution. For the water seepage problem, namely the subdivision research area, a water flow function expression in each subarea is constructed by using a simpler function and is integrated to form a linear function group, and finally the solution of the original water seepage area is obtained by solving.
Specifically, for the interior of the pit, a water supply function is established by considering the water-resisting boundary conditions around the foundation pit.
The water-resisting boundary condition refers to the state of flow elements (water head, speed or speed potential) on the boundary around the groundwater seepage field. The boundary refers to the interface between the water seepage field and the non-water seepage field in the up-down direction and the peripheral direction; the state of the flow element on the boundary refers to all the states on the boundary from the beginning to the time when the calculation is needed. The water-blocking boundary condition is used for indicating that the flow elements in the seepage field are continuously influenced on the boundary.
And if the average water flow supply quantity outside the pit received by the unit area in the pit at the time t is q (t), the water flow supply function is as follows:
in the formula, h is the water level of the node with the coordinate (x, y) at the time t; b is the bottom plate elevation of the aquifer at the coordinate (x, y); w is the number of pumping well points, kx、kyPermeability coefficients in x and y directions; x is the number ofw、ywCoordinates of the pumping well point; qwFor the flow of the well point for pumping water, Q during pumping waterwPositive, Q during rechargewIs negative;
is a singular function, the singular function value being 1 when the independent variables are zero, otherwise zero, the objective being to pump the well point flow QwConverted to an average function over the calculated area.
The bottom plate elevation B of the aquifer is a horizontal plane without flow conversion. In actual works, the aquifer floor may be a clay or rocky roof, which is generally not an ideal horizontal plane, and the aquifer floor elevation input in the flow replenishment function is the regional aquifer floor. For the local area, different aquifer bottom plate elevations can be selected by adopting non-homogeneous elements.
Further, in the water flow replenishment function,
n is the number of light well points outside the pit; s2 is a second flow boundary, i.e., a foundation pit protective structure.
h0(x, y) is the initial water level at the coordinates (x, y) before precipitation,
the water level of the node with coordinates (x, y) at time t = 0.
And for the outside of the pit, the water flow supplement amount received in the pit is actually the water flow loss amount outside the pit, and a water flow loss function is established, so that the analysis on how to virtually arrange a series of light well points on the periphery of the foundation pit is carried out.
And making the total water pumping quantity of the plurality of pumping well points equal to the total water flow loss quantity outside the pit. The calculated boundary outside the pit must be taken far away as the first flow boundary, and the water loss function is as follows:
qNpumping volume for a single light well point, xN、yNAnd the coordinates of the light well points.
S1 and h1(x, y, t) respectively represent a first flow boundary and a first flow edgeWater level at the boundary.
The combination of the two water flow supply functions and the water flow loss function is a complete calculation function when the relation of water flow inside and outside the pit is considered, q (t) is equal to zero when precipitation starts, the water flow supply function is solved to obtain the water level of each node inside the pit at the end of the first period, and the initial water level of each node outside the pit is known; averaging the water levels of all nodes in the pit to obtain an average water level hm; and calculating the average value of the node water levels in a certain range outside the pit to obtain the average water level Hm, wherein the range is the range influenced by precipitation.
Calculating the average water flow replenishment quantity q per unit area in the pit outside the pit in the time period, namely the average value of q (t) in the water flow replenishment function, wherein q is calculated according to the following formula:
q=b（Hm–hm）/(d1+2d2) ；
b is depth d in FIG. 21And d2Solving a water flow replenishment function according to the weighted average value of the vertical permeability coefficients of the soil bodies in the two ranges and the average water flow replenishment quantity q to obtain the water level value of each node in the pit at the end of the next period;
let q' = qA; wherein A is the area of the side surface of the foundation pit, q' is the sum of the pumping quantities of the light well points at the periphery of the foundation pit, and q in the water flow loss function is madeNAnd (= q'/N), wherein N is the number of extra-pit light well sites.
Solving a water flow loss function to obtain the water level of each node outside the pit at the end of the next period; the above calculation process is repeated until the calculation period ends.
Under the action of negative pressure generated by vacuum, the underground water is sucked into the main pipe through a plurality of suction well points and is pumped away, so that the height of the nearby underground water level is reduced. Along with the work of the water pump, a pressure difference exists between the water level of the negative pressure action area and the external water level, and under the action of the pressure difference, underground water outside the negative pressure area moves along the gravity direction, so that vacuum forced pumping is carried out after a plurality of light well points which need to be arranged on the periphery of the foundation pit protection structure are calculated according to a complete calculation function. Only when the negative pressure and gravity act together, the suction well point can work normally.
The pumping well point precipitation is suitable for various sandy soils with the permeability coefficient of less than 20m/d, the single-layer depth reduction is less than 6.5m, and the double-layer depth reduction is less than 13 m. Because the distance between the pumping well points is smaller, the underground water can be effectively prevented from permeating into the foundation pit, the stability of the foundation pit side slope is facilitated, and the actual application effect of the engineering is good. The flow of water in a void medium is called percolation, which, for soil, is the result of the interaction of water with the soil, which has a permeability, expressed as the permeability coefficient k.
As shown in fig. 2, which is a schematic sectional view of a foundation pit pipe well combined light well point system, z is the height of water flow at a position x away from the central axis of a pumping well point, the average flow velocity v = k × dz/dx of a water seepage section is calculated, k is a permeability coefficient, the area of the water seepage section, namely the side surface of the foundation pit, is A,
；
water yield of the water seepage section:
，
variables were separated and integrated on both sides:
taking boundary conditions x = R and z = H to obtain:
substituting C to obtain a seepage flow field function:
the above formula is a seepage flow field function, and the water level depth z in the pit area and at the position x away from the pumping well point axis is obtained.
Wherein R is the radius of a circle surrounded by the light well points (shown as a dotted line in figure 1), H is the depth of the underground water-containing layer, and k is the permeability coefficient of the soil.
After the well point dewatering equipment starts to work, a funnel-shaped falling curved surface can be formed in a certain distance around the dewatering equipment, and the curved surface is gradually close to the original underground water level at a place far away from the well. Therefore, an approximate concept is often introduced in the water seepage calculation, the influence of water pumping is considered to have an influence radius, a light well point is virtually arranged at the influence radius, the underground water level is basically not influenced by descending and draining water in the area outside the influence radius, and the underground water still keeps the original underground water level. The introduction of the concept of influencing the radius also helps to solve the problem of determining the size of the water seepage area in the water seepage finite element calculation.
In the process of water drainage, the water seepage phenomenon occurs within the influence radius. The groundwater moves to the pumping well within the influence radius, the water level falls, and the groundwater level outside the influence radius keeps constant and does not seep water. The precipitation impact radius may thus be borrowed to help determine the range of the water seepage calculation.
According to the calculated water level depth z of any point at the position of the central axis x of the pumping well point, the deepest water level depth z is obtainedmAnd therefore, the embedding depth H of the pipe well of the foundation pit suction well point is obtained:
the great foundation ditch of area adopts the circular pumping well point of laying, and the buried depth H of the tube well of pumping well point:
H≥zm。
according to the total water inflow Q, considering a utilization coefficient, wherein the utilization coefficient is 1.1, and the number W =1.1Q/p of the pumping well points is calculated;
p is the tube well suction for a single suction well point.
And constructing the light well points according to the quantity W of the pumping well points and the burying depth H of the pipe well of the pumping well points.
As shown in fig. 3, a flow chart of the hydraulic engineering foundation pit and pipe well combined light well point dewatering and drainage method of the present invention is shown, a dewatering and drainage system is set according to the number of light well points, the number of pumping well points and the embedding depth of the pumping well points, the dewatering and drainage effect is obvious, and after the pipe well spacing of the pumping well points is increased, the dewatering and drainage requirements can be completely met as long as the pumping capacity of the pipe well of a single pumping well point is correspondingly increased.
Meanwhile, the foundation pit foundation surface has different depths and different requirements on the drainage depth, so that the drainage system has direct influence on the number of the pumping wells and the total water pumping quantity.
In a preferred embodiment, the interval between the suction well points is 40m, the number of the suction well points is 110, and the suction volume of the single-pipe well is 1800m3And in the time of/d, the precipitation effect is very obvious.
In the construction process of the drainage method, after the pipe well of the pumping well point is cleaned and sunk to the pre-calculated embedding depth H by water, a layer of coarse sand is added at the bottom of the pipe well, and then the pipe well is embedded at the pumping well point, so that the perpendicularity, the diameter, the distance and the depth of the pipe well are ensured.
The use of light well points must ensure uninterrupted operation of the drainage process. When no water or turbid water appears, the equipment needs to be repaired and adjusted immediately.
In the preferred embodiment, the vacuum degree in the pipe well at the pumping well point is kept between 55.3 MPa and 66.7MPa, which is the basis for evaluating the working condition of the pipe well equipment. If the gas leakage is not within the range, the gas leakage phenomenon is serious probably because the connection condition of the pipe well is poor, and the gas leakage phenomenon must be repaired immediately.
When the pumping well point works, continuous pumping work needs to be ensured, and 2 power supply devices are used simultaneously, so that power failure is avoided. And after the water is drained for 3-5 days usually, accumulated water is drained, and the water level is kept stable. In the drainage process, different pipeline interfaces need to be checked every day, and the phenomenon that drainage is not smooth due to air leakage is prevented.
As shown in fig. 4, another embodiment of the present invention is provided, in which a plurality of sub-light well points are virtually arranged on the periphery of the light well points, and the arrangement positions of the sub-light well points are staggered with those of the light well points.
And making the total water pumping quantity of the plurality of pumping well points equal to the total water flow loss quantity outside the pit. When the calculation boundary outside the pit is selected, the calculation boundary is farther than the first flow boundary and is used as a secondary flow boundary, and the overall water flow loss function is as follows:
qNpumping volume for a single light well point, xN、yNThe coordinates of the light well points are obtained; q. q ofN1Pumping volume for a single sub-light well point, xN1、yN1The coordinates of the second light well point.
In the embodiment, the water flow replenishment function and the total loss function are combined to form a complete calculation function when the relation between the water flow inside and outside the pit is considered, q (t) is equal to zero when precipitation starts, the water flow replenishment function is solved to obtain the water level of each node inside the pit at the end of the first period, and the initial water level of each node outside the pit is known; averaging the water levels of all nodes in the pit to obtain an average water level hm; and calculating the average value of the node water levels in a certain range outside the pit to obtain the average water level Hm, wherein the range is the range influenced by precipitation.
Calculating the average water flow replenishment amount q per unit area in the pit outside the pit in the time period, namely the average value of q (t) in the water flow replenishment function, wherein q is calculated according to the following formula:
q=b（Hm–hm）/(d1+2d2)；
b is depth d in FIG. 21And d2Solving a water flow supply function according to the weighted average value of the vertical permeability coefficients of the soil bodies in the two ranges and the average water flow supply quantity q to obtain the water level value of each node in the pit at the end of the next period;
let q' = qA; wherein A is the area of the side surface of the foundation pit, q' is the sum of the pumping capacity of the light well point and the pumping capacity of the sub-light well point at the periphery of the foundation pit, and q in the water flow loss function is made to be the sumN= qN1= q'/(N + N1) where N is the number of extra-pit light well sites and N1 is the extra-pit secondary light wellThe number of points.
Solving a water flow loss function to obtain the water level of each node outside the pit at the end of the next period; the above calculation process is repeated until the calculation period is over.
In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the application to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in or transmitted over a computer-readable storage medium. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.
While the invention has been described with reference to specific embodiments, the scope of the invention is not limited thereto, and those skilled in the art can easily conceive various equivalent modifications or substitutions within the technical scope of the invention. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (5)
1. Water conservancy project foundation pit tube well combines light well point and falls drainage method, its characterized in that includes:
establishing a water flow replenishment function by considering the water-resisting boundary conditions around the foundation pit;
virtually arranging a plurality of light well points on the periphery of the foundation pit, and establishing a water flow loss function;
the water flow supply function and the water flow loss function are combined to form a complete calculation function of water flow relation inside and outside the pit;
calculating the number of the light well points needing to be arranged through the complete calculation function;
calculating the deepest water level depth of the foundation pit and the embedding depth of a suction well point of the foundation pit through a seepage flow field function;
calculating the number of the pumping well points of the foundation pit based on the total water inflow;
and performing drainage system construction according to the number of the light well points, the number of the pumping well points and the burying depth of the pumping well points.
2. The hydraulic engineering foundation pit and pipe well combined light well point water lowering and draining method according to claim 1,
the water flow replenishment function is:
the water flow loss function is:
in the formula, h is the water level of a node with coordinates (x, y) at the moment t; q (t) is the average water flow supply received by the unit area in the pit at the time t; b is the bottom plate elevation of the aquifer at the coordinate (x, y); n is the number of light well points, W is the number of pumping well points, kx、kyPermeability coefficients in x and y directions; x is the number ofw、ywCoordinates of the pumping well point; qwIn order to pump the well point flow rate,
is a singular function; q. q.sNPumping volume for a single light well point, xN、yNAnd the coordinates of the light well points.
3. The hydraulic engineering foundation pit, pipe and well combined light well point water lowering and draining method according to claim 2, wherein q (t) is equal to zero when water lowering starts, a water flow supply function is solved to obtain the water level of each node in the pit at the end of the first period, and the initial water level of each node outside the pit is known;
averaging the water levels of all nodes in the pit to obtain an average water level hm; calculating the average value of the water levels of the nodes outside the pit to obtain an average water level Hm;
calculating the average water flow replenishment quantity q of the outside of the pit to the inside of the pit on the unit area:
q=b（Hm–hm）/(d1+2d2) ；
b is d1、d2Weighted average value of vertical permeability coefficient of soil body in the range;
solving a water flow supply function according to the average water flow supply quantity q to obtain the water level value of each node in the pit at the end of the next period;
let q' = qA; wherein A is the side area of the foundation pit, q' is the sum of the pumping quantities of light well points at the periphery of the foundation pit, and q in the water flow loss function is madeN= q'/N, where N is the number of extra-pit light well points; solving a water flow loss function to obtain the water level of each node outside the pit at the end of the next period;
the above calculation process is repeated until the end of the calculation period.
4. The hydraulic engineering foundation pit and pipe well combined light well point dewatering and drainage method as claimed in claim 1, wherein the calculating of the deepest water level depth of the foundation pit and the burying depth of the suction well point of the foundation pit through the seepage flow field function comprises:
z is the height of the flow field at the position x away from the axis of the pumping well point, and the average flow velocity of the water seepage section is calculatedv = k × dz/dx, k is permeability coefficient, the side area of the foundation pit is A,
；
water yield of the water seepage section:
,
separate variables, integrate on both sides:
taking boundary conditions x = R and z = H to obtain:
substituting C to obtain a seepage flow field function:
according to the water level depth z, taking the deepest water level depth zm，
The embedding depth H is more than or equal to zm。
5. The water conservancy project foundation pit and pipe well combined light well point water drainage method according to claim 1, characterized in that according to total water inflow Q, a utilization coefficient is set to be 1.1, and the number W =1.1Q/p of pumping well points is calculated; p is the tube well suction for a single suction well point.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115408886A (en) * | 2022-10-28 | 2022-11-29 | 德州黄河建业工程有限责任公司维修养护分公司 | Water lowering and draining system and method for controlling underground structure settlement through hydraulic engineering |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005002659A (en) * | 2003-06-11 | 2005-01-06 | East Japan Railway Co | Groundwater circulation system in excavation of ground, and construction method for measure against groundwater in excavation of ground |
| CN103967028A (en) * | 2014-05-27 | 2014-08-06 | 江苏南通三建集团有限公司 | Immersed tube drainage structure and method for handling suddenly-produced foundation pit water bursting and fountains through immersed tube drainage structure |
| KR20140096731A (en) * | 2013-01-29 | 2014-08-06 | 한국지질자원연구원 | Underground water drainage system of excavated ground and pipeline construction method using the same |
| CN109972643A (en) * | 2019-05-06 | 2019-07-05 | 中国人民解放军空军工程大学 | A kind of region of FuShui base pit engineering Trinity joint precipitation system |
| CN110777830A (en) * | 2019-08-30 | 2020-02-11 | 中电建十一局工程有限公司 | Foundation pit dewatering control method under geological condition of water-rich thick gravel layer |
| CN112160324A (en) * | 2020-08-25 | 2021-01-01 | 南通大学 | Construction method for deep foundation pit support |
| CN114108656A (en) * | 2021-12-27 | 2022-03-01 | 南通大学 | Construction method of foundation pit support |
-
2022
- 2022-05-23 CN CN202210560847.XA patent/CN114658018A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005002659A (en) * | 2003-06-11 | 2005-01-06 | East Japan Railway Co | Groundwater circulation system in excavation of ground, and construction method for measure against groundwater in excavation of ground |
| KR20140096731A (en) * | 2013-01-29 | 2014-08-06 | 한국지질자원연구원 | Underground water drainage system of excavated ground and pipeline construction method using the same |
| CN103967028A (en) * | 2014-05-27 | 2014-08-06 | 江苏南通三建集团有限公司 | Immersed tube drainage structure and method for handling suddenly-produced foundation pit water bursting and fountains through immersed tube drainage structure |
| CN109972643A (en) * | 2019-05-06 | 2019-07-05 | 中国人民解放军空军工程大学 | A kind of region of FuShui base pit engineering Trinity joint precipitation system |
| CN110777830A (en) * | 2019-08-30 | 2020-02-11 | 中电建十一局工程有限公司 | Foundation pit dewatering control method under geological condition of water-rich thick gravel layer |
| CN112160324A (en) * | 2020-08-25 | 2021-01-01 | 南通大学 | Construction method for deep foundation pit support |
| CN114108656A (en) * | 2021-12-27 | 2022-03-01 | 南通大学 | Construction method of foundation pit support |
Non-Patent Citations (3)
| Title |
|---|
| 任红林等: "基坑工程井点降水分析计算", 《水文地质工程地质》 * |
| 曹宝山: "采用组合降水解决互层土基坑难于开挖的问题", 《中小企业管理与科技》 * |
| 赵志缙等: "《简明深基坑工程设计施工手册》", 30 April 2000 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115408886A (en) * | 2022-10-28 | 2022-11-29 | 德州黄河建业工程有限责任公司维修养护分公司 | Water lowering and draining system and method for controlling underground structure settlement through hydraulic engineering |
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