CN-122020792-A - Seepage analysis method for sluice foundation diaphragm wall and bored concrete pile synergistic effect

Abstract

The invention relates to a seepage analysis method for the synergy of a sluice foundation diaphragm wall and a filling pile, which is characterized by analyzing a seepage field according to Darcy's law of seepage and a water flow continuity equation, converting to obtain a finite element method to solve the equation of the seepage field, establishing a model, defining material parameters of the model after the finite element model is established, setting seepage working conditions respectively corresponding to different sluice upstream water level conditions so as to simulate the seepage field characteristics of the sluice under different operation working conditions, comprehensively evaluating the seepage condition of the sluice under different water levels, and analyzing and calculating the sluice seepage under the synergy of the diaphragm wall and the filling pile.

Inventors

• QIU CHANGJIE
• ZHANG HUAN
• LI ZIHUI
• HUANG WEITAO
• CHEN HONGJIE
• WU QIUHUA
• SHI JIHUI
• WANG MINGANG
• XIA HOUXING
• YAO LILI
• CHEN YUNZHOU
• WEI DANNA

Assignees

• 福建省水利水电勘测设计研究院有限公司

Dates

Publication Date

20260512

Application Date

20260127

Claims (3)

1. 1. The seepage analysis method for the cooperation of the sluice foundation diaphragm wall and the filling pile is characterized by comprising the following steps: First, principle of calculation The basic differential equation for stable seepage can be expressed as: 1-1 In the formula, Is a partial differential symbol, x, y and z are space coordinates for describing the position of any point in a seepage field, k is a seepage coefficient, H is a water head and is measured in units of meters; when deriving the rock mass osmotic tensor, the expression of the osmotic energy in a certain osmotic region can be obtained as follows: 1-2 Wherein I is energy dissipation rate density or hydraulic power density, and d is volume infinitesimal; (1) For stable seepage, the solution condition of the basic differential equation is only a boundary condition, and the common boundary conditions are as follows: (a) Boundary conditions of the first type, when the head of water at a certain part of the boundary of the percolation region is known and the normal flow rate is unknown, the boundary conditions can be expressed as: 1-3 In the formula, As a head function, S1 is a known head boundary; (b) Boundary conditions of the second type, when the normal flow velocity at a certain part of the boundary of the percolation region is known and the head is unknown, the boundary conditions can be expressed as: 1-4 Wherein n is the external normal direction, q is the inflow/outflow rate per unit area on the boundary of the seepage area, and S2 is the boundary of the known flow rate; (c) Boundary conditions of free surface and overflow surface boundary conditions of pressureless percolation free surface can be expressed as: 1-5 1-6 Wherein S3 is a free surface boundary; The boundary conditions of the overflow surface are: 1-7 1-8 Wherein S4 is the boundary of the overflow surface; (2) In the analysis of a seepage field, the existence of a solution condition, the uniqueness of the solution and the stability of the solution are required to be met, the problem that the three conditions are met is called a proper problem, and according to the above, the three-dimensional stable seepage problem can be summarized as the following solution problem: 1-9 1-10 1-11 (3) According to the principle of variation, the above-mentioned solution problem is equivalent to the extremum problem of solving the energy functional: 1-12 According to the hydrogeologic structure of the research area, discretizing the seepage field, namely: 1-13 Taking the variation of the formula 1-12 to be equal to zero, and superposing all the subareas to obtain an equation for solving the seepage field by a finite element method: 1-14 Wherein: The matrix is penetrated in the whole body, -The water head value of each node, -Equivalent node traffic column vector; Secondly, establishing a finite element numerical model containing the seepage wall and the filling pile and the seepage parameters of each soil layer and the structural materials according to the calculation principle; Third, by setting the upstream water level conditions under different working conditions, the key seepage parameters of the seepage flow, the flow velocity distribution, the water head field and the hydraulic gradient corresponding to the model are calculated based on the analysis of the calculation principle, and the seepage flow condition of the sluice under different water levels is comprehensively estimated.
2. 2. The seepage analysis method for the synergistic effect of the sluice foundation diaphragm wall and the filling pile according to claim 1 is characterized in that in the step (three), the three working conditions are working condition A corresponding to the highest water level of 4.08m under the normal operating condition, working condition B corresponding to the designed flood level of 7.48m and working condition C corresponding to the check flood level of 8.36m respectively.
3. 3. The method for analyzing seepage of a sluice foundation diaphragm wall and a bored concrete pile according to claim 1 or 2, wherein in the step (three), the seepage coefficient and the water supply degree parameter of the diaphragm wall and the bored concrete pile in the finite element numerical model are respectively 0.

Description

Seepage analysis method for sluice foundation diaphragm wall and bored concrete pile synergistic effect Technical Field The invention relates to a seepage analysis method for the synergistic effect of a sluice foundation diaphragm wall and a filling pile. Background The stable seepage is a seepage mode in which the physical quantities such as pressure, flow speed and the like are only changed along with the spatial position and are irrelevant to time when the fluid flows in the porous medium. The core characteristics of the device are that the head difference between the upstream and the downstream is constant, the medium is in a saturated laminar flow state, and the device is commonly found in the scenes of oil reservoir development, earth dam seepage and the like driven by rigid water pressure. The seepage flow, the seepage speed, the water head water pressure equivalent distribution and the water power slope under different materials and structures are different. The prior art does not have a seepage analysis method under the synergistic effect of the impervious wall and the filling pile in the sluice foundation. Conventional gate-based barrier designs have focused on vertical barrier (e.g., sheet piles, underground diaphragm walls) or horizontal barrier cladding, with the core objective of extending the percolation path and reducing the hydraulic ramp down. However, in many practical projects, the underlying treatment of the sluice is not limited to seepage prevention. In order to meet the requirements of bearing capacity, sedimentation control, anti-slip stability and the like, pile foundations such as cast-in-place piles or stirring piles are generally arranged in a large-scale foundation. The downstream pile foundations objectively change the permeability characteristics of foundation soil and form a second invisible seepage-proofing or water-proofing barrier. If their presence is ignored, the seepage analysis is performed only on the natural foundation or on a simplified model of the wall only, which results in the following problems: overestimating the seepage risk, namely neglecting the water blocking effect of the pile foundation, wherein the calculated seepage flow, the calculated flow velocity and the calculated hydraulic gradient can be obviously higher than the actual value, so that the design is too conservative, and unnecessary seepage prevention investment is increased; Underestimating the synergistic efficiency, namely, failing to quantitatively evaluate the real effect of the wall-pile combined seepage prevention system, possibly missing the opportunity of optimizing a design scheme (such as properly thinning the depth of the seepage prevention wall), so that the optimal balance of safety and economy is difficult to realize; And (3) analyzing model distortion, namely, causing deviation between the calculated subgate seepage field, the equivalent water head line and pore water pressure distribution and the actual working condition, and affecting accurate judgment of seepage stability. Therefore, the collaborative seepage analysis of the impervious wall and the filling pile is carried out, so that the actual working state of the sluice is simulated more truly, finely and economically, and the engineering design is a necessary requirement from 'empirical' to 'accurate'. Disclosure of Invention The invention aims to provide a seepage analysis method for the synergistic effect of a sluice foundation diaphragm wall and a filling pile, which can be used for carrying out seepage analysis under the synergistic effect of the sluice foundation diaphragm wall and the filling pile and can simulate the actual working state of a sluice more truly, finely and economically. The technical scheme of the invention is that the seepage analysis method for the synergistic effect of the sluice foundation diaphragm wall and the filling pile comprises the following steps: First, principle of calculation The basic differential equation for stable seepage can be expressed as: 1-1 In the formula,Is a partial differential symbol, x, y and z are space coordinates for describing the position of any point in a seepage field, k is a seepage coefficient, and H is a water head per meter; when deriving the rock mass osmotic tensor, the expression of the osmotic energy in a certain osmotic region can be obtained as follows: 1-2 Wherein I is the energy dissipation ratio density (or hydraulic power density), and d is the volume infinitesimal. (1) For stable seepage, the solution condition of the basic differential equation is only a boundary condition, and the common boundary conditions are as follows: (a) Boundary conditions of the first type, when the head of water at a certain part of the boundary of the percolation region is known and the normal flow rate is unknown, the boundary conditions can be expressed as: 1-3 In the formula,As a head function, S1 is a known head boundary; (b) Boundary conditions of the second type, w