CN111414660B - Monte Carlo-based method for analyzing influence of pile position deviation uncertainty on seepage prevention - Google Patents
Monte Carlo-based method for analyzing influence of pile position deviation uncertainty on seepage prevention Download PDFInfo
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Abstract
The invention belongs to the technical field of geotechnical engineering, and discloses a method for analyzing the influence of pile position deviation uncertainty on seepage prevention based on Monte Carlo. The method can evaluate the influence of the pile position deviation on the anti-seepage effect, and can be applied to the prevention and remediation of water stop quality accidents in the construction process.
Description
Technical Field
The invention relates to the technical field of geotechnical engineering, in particular to a method for analyzing influence of pile position deviation uncertainty on seepage prevention based on Monte Carlo.
Background
In recent years, along with the development of society and economy in China and the continuous promotion of modern construction, practitioners in the field of engineering construction continuously and deeply research disaster control, the related fields are more and more extensive, and particularly, the research on water disaster control reaches a new height.
In the engineering construction process, special foundations are often required to be treated, and the control of underground water is enhanced. Meanwhile, underground water control is also an important work content of foundation pit support, and the control method mainly comprises precipitation, water stop, water collection and surface drainage and the like. In northern areas of China, the underground water level is generally low, the control is usually carried out by adopting a first method, and when the underground water level in southern areas is higher, a water stopping method is utilized. However, when the measures for precipitation are taken, water resources are wasted, and uneven settlement is caused to the surrounding ground surface. Therefore, in order to control underground water and ensure construction safety, some northern areas have also been provided with a management method for precipitation construction, and the application of the waterproof curtain of the foundation pit engineering is increased. Meanwhile, in engineering construction, a weak foundation and a bad foundation which cannot directly bear all loads of a building and a structure often exist, and how to treat the foundations becomes a big problem in the engineering construction. The quality of foundation treatment is related to the quality, cost and construction period of the whole project, and the safety of buildings and structures is directly influenced. The high-pressure jet grouting pile is a common process for treating and reinforcing foundation, supporting and stopping water in foundation pit. In the construction of deep foundation pit, it is often combined with cast-in-place pile to respectively undertake the functions of supporting foundation pit wall and stopping water, and at the same time, the jet grouting pile reinforces the soil body of pit wall to reduce the soil pressure for supporting cast-in-place pile body.
Although foundation treatment techniques are widely used in engineering construction, many cases of water failure or unstable support have occurred. In the general pore-forming process of pile construction, due to design deviation, geological conditions, construction process and other reasons, the pile position deviates, so that the pile foundation deviates, a tight waterproof curtain cannot be formed, water stop quality accidents in the engineering are caused, and serious economic loss is caused to the engineering. Therefore, the pile position deviation in the construction process is quantified, the influence of the pile position deviation on the water stopping effect is evaluated, and the method has very important significance for preventing and remedying the water stopping quality accidents in the construction process.
Disclosure of Invention
The invention aims to provide an analysis method for analyzing the influence of uncertainty of pile position deviation on seepage prevention based on Monte Carlo, which is used for quantifying the pile position deviation in the construction process and evaluating the influence of the pile position deviation on the seepage prevention effect and can be applied to the prevention and the remedy of water stop quality accidents in the construction process.
The embodiment of the application provides a method for analyzing the influence of pile position deviation uncertainty on seepage prevention based on Monte Carlo, which comprises the following steps:
2, simulating the seepage flow passing through the simulation area by adopting a Monte Carlo method;
and 3, analyzing the influence of pile position deviation on the seepage-proofing effect by taking the seepage flow acquired by simulation as an evaluation index.
Preferably, in step 1, the input parameter includes a maximum pile position deviation angle.
Preferably, the input parameters further include: permeability coefficient information, geometric size information;
the permeability coefficient information comprises the permeability coefficient of the pile and the permeability coefficient of the land in the simulation area;
the geometric dimension information comprises the number of piles and the dimension information of the piles; the size information of the piles includes diameters of the piles, lengths of the piles, and overlapping lengths between the piles.
Preferably, in the step 1, the seepage-proofing influence simulation model randomly generates a pile position deviation amount corresponding to each pile by using a random algorithm;
the pile position deviation amount corresponding to each pile is less than or equal to the maximum pile position deviation value, and the maximum pile position deviation value meets the following formula:
dmax＝β×He
in the formula (d)maxRepresents the maximum pile position deviation value, beta represents the maximum pile position deviation angle, HeIndicating the length of the pile.
Preferably, in the seepage-proofing influence simulation model, the top of the pile is set to be free of deviation, the central positions of the bottom of the pile are set to be randomly distributed in a circle with a diameter of a first diameter, and the first diameter adopts the maximum pile position deviation value.
Preferably, the coordinates (d) of the centre of the bottom of the pilex,dy) Expressed as:
dx＝d×cosθ
dy＝d×sinθ
in the formula (d)maxRepresenting the maximum pile position deviation value; rand denotes a random number, rand being [0,1 ]]Uniformly distributing the upper layer; d represents the deviation value of the pile position and satisfies d is less than or equal to dmax(ii) a Theta represents an azimuth angle in polar coordinates generated randomly, and theta is subjected to uniform distribution in [0,2 pi ];
bottom contour of pile (x)z,yz) Expressed as:
xz＝x0+dx×cosα
yz＝y0+dy×sinα
in the formula, x0、y0And (3) representing the horizontal and vertical coordinate values of the axis of the pile under the design condition, wherein alpha represents the azimuth angle under the polar coordinate and belongs to [0,2 pi ].
Preferably, in the step 2, the simulating the seepage flow passing through the simulation area comprises the following substeps:
carrying out finite element meshing aiming at the seepage-proofing influence simulation model;
applying a boundary condition to the simulation area based on Darcy's law;
and under the given boundary condition, carrying out finite element solving calculation on the seepage-proofing influence simulation model to obtain the seepage flow passing through the simulation area.
Preferably, the boundary conditions are: applying a water head difference on the front surface and the rear surface of the simulation area, and setting other surfaces of the simulation area as watertight boundaries;
the seepage flow through the simulation zone is expressed as:
ΔQ/Δt＝vA＝kiA
in the formula, Δ Q/Δ t represents the amount of permeation flux passing per unit time, k represents the permeability coefficient, a represents the cross-sectional area orthogonal to the water flow direction, and i represents the hydraulic gradient.
Preferably, in the step 3, for an input parameter corresponding to a certain working condition, the number of times of leakage occurring in the N monte carlo simulations is counted, and the average leakage flow rate obtained in the N monte carlo simulations is counted; analyzing the influence of a certain pile position deviation on the seepage-proofing effect according to the seepage times and the average seepage flow;
comparing the leakage times and the average leakage flow obtained under the input parameters corresponding to different working conditions, and analyzing the influence of different pile position deviations on the anti-seepage effect;
and when the seepage quantity acquired in the simulation is greater than 0, judging that the seepage phenomenon occurs.
Preferably, the step 2 further comprises: simulating the distribution information of the simulation area; the distribution information comprises water head distribution information and water flow density distribution information;
the step 3 further comprises: and (4) taking the distribution information acquired by simulation as an auxiliary evaluation index to assist in analyzing the influence of pile position deviation on the anti-seepage effect.
One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:
in the embodiment of the application, an anti-seepage influence simulation model is established, input parameters corresponding to the anti-seepage influence simulation model are determined according to working conditions, then the seepage flow passing through a simulation area is simulated by adopting a Monte Carlo method, and finally the seepage flow collected by simulation is used as an evaluation index to analyze the influence of pile position deviation on the anti-seepage effect. The method can realize the simulation of the seepage flow under the pile position deviation in the design working condition and the actual working condition based on the Monte Carlo method, and thus the influence of the seepage flow on the permeability is researched. The method combines the practical engineering problems, can quantitatively evaluate the influence of the uncertainty of the pile position deviation on the seepage-proofing performance of the pile position deviation, and is used for reference on the prevention and the remedy of the water stopping quality accidents in the construction process of geotechnical engineering. The method is simple and easy to implement, and is quick and convenient.
Drawings
In order to more clearly illustrate the technical solution in the present embodiment, the drawings needed to be used in the description of the embodiment will be briefly introduced below, and it is obvious that the drawings in the following description are one embodiment of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
Fig. 1 is a schematic frame diagram of an analysis method for analyzing an anti-seepage effect based on a pile position deviation uncertainty of monte carlo according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of boundary conditions in an analysis method for an anti-seepage effect based on a pile position deviation uncertainty of monte carlo according to an embodiment of the present invention.
Fig. 3 is a speed vector cloud chart under a design condition (no pile position deviation) and an actual condition (a maximum pile position deviation angle is 2%).
Fig. 4 is a top view velocity vector cloud of the pile bottom under the actual working condition (the maximum pile position deviation angle is 2%).
Fig. 5 is a schematic diagram of randomness of 3 different pile position deviations (maximum pile position deviation angles are 0.5%, 1%, and 2%, respectively).
Fig. 6 is a statistical chart of seepage times of a seepage site appearing in 100 monte carlo simulation results under 3 different pile position deviations (maximum pile position deviation angles are 0.5%, 1% and 2%, respectively).
Fig. 7 is a statistical chart of seepage in 100 monte carlo simulation results under 3 different pile position deviations (maximum pile position deviation angles are 0.5%, 1%, and 2%, respectively).
Detailed Description
In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.
Example 1
The embodiment 1 provides a method for analyzing the influence of pile position deviation uncertainty on seepage prevention based on Monte Carlo, and with reference to FIG. 1, the method mainly comprises the steps of inputting parameters and Monte Carlo simulation times, establishing a model, performing numerical simulation, recording seepage flow and calculating statistics.
The specific steps are explained below.
One key parameter in the input parameters is a maximum pile position deviation angle, and represents a maximum deviation range. Other input parameters also comprise permeability coefficient information and geometric dimension information; the permeability coefficient information comprises the permeability coefficient of the pile and the permeability coefficient of the land in the simulation area; the geometric dimension information comprises the number of piles and the dimension information of the piles; the size information of the piles includes diameters of the piles, lengths of the piles, and overlapping lengths between the piles.
Namely, the input parameters corresponding to the model comprise input parameters such as the size of the pre-simulation area and the number and the size of the piles. And determining each parameter value according to actual engineering requirements, industrial specifications and the like. Specifically, the model size under the design condition is determined, and important information such as the diameter of the piles, the length of the piles, the overlapping length between the piles, the maximum pile position deviation angle (maximum deviation range), the number of the piles and the like is included.
The parameters of different projects are different, so the number, diameter, length and the like of the piles need to be calibrated according to specific project requirements. Typically, the overlapping length of the stakes is 200-300 mm. Different projects have different requirements on the allowable verticality of the drilled hole. As specified in Highway engineering quality inspection and assessment Standard, the pile position deviation of a single-row pile is 50mm, and if the pile position deviation exceeds the limit, the stress performance of the bridge foundation is influenced to a certain extent.
The seepage-proofing influence simulation model mainly comprises two parts: columns and untreated soil. And carrying out random simulation under the condition of giving the maximum pile position deviation.
Specifically, an anti-seepage influence simulation model is established, and randomness of pile position deviation is achieved through a random algorithm. The seepage-proofing influence simulation model randomly generates a pile position deviation amount corresponding to each pile by using a random algorithm; and the pile position deviation amount corresponding to each pile is less than or equal to the maximum pile position deviation value.
At the earth's surface (i.e. the pile top), the pile is drilled according to the designed position without deviation. With the increase of the depth, the position deviation of the pile position is more and more likely to occur. Generally, the randomness of the axial position of the pile can be described by two parameters: azimuth angle alpha of the axial position of the pile and inclination angle beta of the axial position of the pile. Where the azimuth angle alpha of the axial position of the pile follows a uniform distribution of 0,2 pi), indicating that the pile can be tilted in any direction. Wherein, the maximum pile position deviation value satisfies the following formula:
dmax＝β×He
in the formula (d)maxRepresents the maximum pile position deviation value, beta represents the maximum pile position deviation angle, HeIndicating the length of the pile.
That is, in the seepage-proofing influence simulation model, the top of the pile is set to be free of deviation, and the central positions of the bottom of the pile are set to be randomly distributed in a circle having a diameter of a first diameter, which is the maximum pile position deviation value.
During simulation, the central O' point of the pile bottom uniformly falls on a diameter dmaxWithin the circle of (c). This problem relates to the problem of disk spotting, at a diameter dmaxThe uniformly distributed random numbers are generated within the circle (i.e., with the maximum peg-level deviation value as the diameter), which can be represented using polar coordinates. Coordinates (d) of the center of the bottom of the pilex,dy) Expressed as:
dx＝d×cosθ
dy＝d×sinθ
in the formula (d)maxRepresenting the maximum pile position deviation value; rand denotes a random number, rand being [0,1 ]]Uniformly distributing the upper layer; d represents the deviation value of the pile position and satisfies d is less than or equal to dmax(ii) a Theta denotes the azimuth angle in polar coordinates generated randomly, theta obeys a uniform distribution over 0,2 pi).
Bottom contour of pile (x)z,yz) Expressed as:
xz＝x0+dx×cosα
yz＝y0+dy×sinα
in the formula, x0、y0And (3) representing the horizontal and vertical coordinate values of the axis of the pile under the design condition, wherein alpha represents the azimuth angle under the polar coordinate and belongs to [0,2 pi ].
Where α is all values from 0 to 2 π, and θ is only one value from 0 to 2 π, θ is randomly generated.
According to the introduction of the basic principle, the establishment of an anti-seepage influence simulation model under the condition of considering pile position deviation can be realized, and further random simulation is carried out under the condition of giving the maximum pile position deviation.
And 2, simulating the seepage flow passing through the simulation area by adopting a Monte Carlo method.
Wherein the simulating the seepage flow through the simulation zone comprises the substeps of:
(1) and carrying out finite element meshing aiming at the seepage-proofing influence simulation model.
Specifically, the established seepage-proofing influence simulation model is imported into finite element calculation software to realize free mesh generation. And the finite element software automatically completes mesh subdivision according to the appearance of the geometric body.
The invention adopts a free mesh generation method, and can automatically realize the mesh generation of the seepage-proofing influence simulation model by means of finite element commercial software. Compared with the background mesh generation method, the method can be automatically attached to the shape of a geometric body, has strong applicability, can automatically complete mesh generation, and cannot cause distortion of boundaries of various materials due to the problems of mesh mapping and the like. The divided grids can better simulate the boundary condition of piles and soil.
(2) Boundary conditions are applied to the simulated region based on darcy's law.
And applying boundary conditions to the simulation sample based on Darcy's law, and evaluating the permeability characteristics.
Specifically, a certain water head difference is applied to the front surface and the rear surface of the simulation area, and the rest surfaces are watertight boundaries. As shown in fig. 2, the front and back surfaces of the model (E, F planes) are subjected to a head differential, with the remainder (a-D planes) being completely water impervious boundaries.
Namely, the boundary conditions are: a water head difference is applied to the front surface and the rear surface of the simulated area, and the other surfaces of the simulated area are set as watertight boundaries.
(3) And under the given boundary condition, carrying out finite element solving calculation on the seepage-proofing influence simulation model to obtain the seepage flow passing through the simulation area.
The seepage flow through the simulation zone is expressed as:
ΔQ/Δt＝vA＝kiA
in the formula, Δ Q/Δ t represents the amount of permeation flux passing per unit time, k represents the permeability coefficient, a represents the cross-sectional area orthogonal to the water flow direction, and i represents the hydraulic gradient.
After the seepage calculation is carried out by finite element software, the seepage flow passing through the simulation area can be obtained so as to evaluate the water stopping effect.
In addition, the optimization scheme also comprises the step of simulating the distribution information of the simulation area. The distribution information comprises water head distribution information and water flow density distribution information. The water head distribution and the water flow density distribution of seepage can be used as references, so that the seepage quantity of which part is larger can be seen more intuitively, and the engineering attention can be paid to.
And 3, analyzing the influence of pile position deviation on the seepage-proofing effect by taking the seepage flow acquired by simulation as an evaluation index.
One application case is: counting the leakage times of the leakage phenomenon in N Monte Carlo simulations according to the input parameters corresponding to a certain working condition, and counting the average leakage flow obtained in the N Monte Carlo simulations; and analyzing the influence of the deviation of a certain pile position on the seepage-proofing effect according to the seepage times and the average seepage flow.
Another application case is: and analyzing the influence of different pile position deviations on the seepage-proofing effect by comparing the seepage times and the average seepage flow obtained under the input parameters corresponding to different working conditions.
In the two application cases, when the seepage quantity acquired by simulation is greater than 0, the seepage phenomenon is judged to occur.
In the preferable scheme, the distribution information acquired by simulation is used as an auxiliary evaluation index to assist in analyzing the influence of pile position deviation on the anti-seepage effect.
In order to better understand the above scheme, example 1 is explained below from another point of view.
1. and determining parameter information under the design condition, establishing an anti-seepage influence simulation model, and realizing the randomness of pile position deviation.
2. And (4) carrying out finite element mesh division aiming at the established seepage-proofing influence simulation model, and applying boundary conditions to the simulation area.
3. And (4) carrying out finite element solution calculation under the given boundary condition, thereby obtaining the seepage flow passing through the whole simulation area.
4. And repeating the steps to perform Monte Carlo simulation for multiple times.
For example, 100 Monte Carlo simulations are performed, and the seepage rate of each simulation is recorded, so as to facilitate statistical law analysis.
It can be seen that example 1 has the following three significant features: the method is combined with engineering practice, and an anti-seepage influence simulation model (namely a numerical simulation model) is established aiming at the uncertain characteristics of pile position deviation. The calculation is simpler, and the possible working conditions in the actual engineering can be well simulated. Secondly, the method is simple in calculation principle, a certain water head difference is applied to the upper surface and the lower surface of the simulation area based on Darcy's law, and the seepage flow passing through the simulation area can be obtained through finite element calculation. And thirdly, the method is based on the Monte Carlo method, repeated calculation can be realized, and the statistical rule of the seepage flow can be conveniently obtained.
Example 2
In embodiment 2, determining the input parameters corresponding to the impermeable influence simulation model includes:
(1) permeability coefficient: the seepage coefficient of the pile is 1 multiplied by 10-9m/s, the permeability coefficient of the soil in the simulated area is 1 x 10-5m/s。
(2) Geometric dimension: 8 piles are cut out of the simulation area, the diameter of each pile is 1.6m, the length of each pile is 20m, and the overlapping length between the piles is 300 mm. The maximum pile position deviation angle is 0.5%, and only half of the left pile and the right pile are reserved to represent that the simulation is equivalent to a section of construction area in the actual engineering.
In embodiment 2, by using the analysis method for the influence of uncertainty of pile position deviation based on monte carlo on the anti-seepage effect, which is provided in embodiment 1, according to finite element calculation, no water flows out in each simulation in 100 monte carlo simulations, and no leakage phenomenon occurs. The condition that the maximum pile position deviation angle is 0.5 percent is shown, and the pile position deviation has no influence on the anti-seepage effect of the pile position deviation angle.
Example 3
In embodiment 3, determining the input parameters corresponding to the impermeable influence simulation model includes:
(1) permeability coefficient: the seepage coefficient of the pile is 1 multiplied by 10-9m/s, the permeability coefficient of the soil in the simulated area is 1 x 10-5m/s。
(2) Geometric dimension: 8 piles are cut out of the simulation area, the diameter of each pile is 1.6m, the length of each pile is 20m, and the overlapping length between the piles is 300 mm. The maximum pile position deviation angle is 1.0%, and only half of the left pile and the right pile are reserved to represent that the simulation is equivalent to a section of construction area in the actual engineering.
Example 4
Embodiment 4 estimates the influence of the pile position deviation on the anti-seepage effect under the working condition that the maximum pile position deviation angle is 2.0% by using the analysis method for the influence of the pile position deviation uncertainty based on the monte carlo on the anti-seepage effect, which is provided in embodiment 1.
In embodiment 4, determining the input parameters corresponding to the anti-seepage influence simulation model includes:
(1) permeability coefficient: the seepage coefficient of the pile is 1 multiplied by 10-9m/s, permeability system of the soil in the simulated areaNumber 1X 10-5m/s。
(2) Geometric dimension: 8 piles are cut out of the simulation area, the diameter of each pile is 1.6m, the length of each pile is 20m, and the overlapping length between the piles is 300 mm. The maximum pile position deviation angle is 2.0%, and only half of the left pile and the right pile are reserved to represent that the simulation is equivalent to a section of construction area in the actual engineering.
Embodiment 4 using the analysis method for the influence of uncertainty of pile position deviation based on monte carlo on the anti-seepage effect, which is provided in embodiment 1, according to finite element calculation, 83 times of seepage phenomena occur in 100 monte carlo simulations, and the average seepage flow is 7.5 × 10-5m3And s. The condition that the maximum pile position deviation angle is 2.0% is shown, and the pile position deviation has obvious influence on the anti-seepage effect of the pile position deviation angle.
In addition, the left graph of fig. 3 is a speed vector cloud under a design condition (no pile position deviation), and the right graph of fig. 3 is a speed vector cloud under an actual condition (the maximum pile position deviation angle is 2%). Fig. 4 is a top view velocity vector cloud of the pile bottom under actual working conditions (the maximum pile position deviation angle is 2%). It can be seen that under the design condition, the pile has a better water stopping effect, and no water passes through the simulation area. Under the working condition that the maximum pile position deviation angle is 2.0%, the integral water stopping effect is influenced to a certain degree, and seepage channels can be generated at the places with poor contact among the piles, so that the engineering safety is damaged, and even serious engineering accidents are caused.
In embodiments 2 to 4, a schematic diagram of randomness of three different pile position deviations with maximum pile position deviation angles of 0.5%, 1.0%, and 2.0% is shown in fig. 5, where the statistical diagram at the uppermost position in fig. 5 corresponds to a case where the maximum pile position deviation angle is 0.5%, the statistical diagram at the middle position in fig. 5 corresponds to a case where the maximum pile position deviation angle is 1.0%, and the statistical diagram at the lowermost position in fig. 5 corresponds to a case where the maximum pile position deviation angle is 2.0%. It can be seen that the pile position deviation amount corresponding to each pile is randomly generated by using a random algorithm under the condition that the maximum pile position deviation angle is determined.
The simulation results of examples 2-4 were compared and analyzed.
As shown in fig. 6, the statistics of the number of times of leakage occurred under three different pile position deviations, i.e., the maximum pile position deviation angles of 0.5%, 1.0%, and 2.0%, are 0, 8, and 83 times, respectively. It is shown that the times of leakage phenomena are gradually increased along with the increase of pile position deviation. The existence of great stake position deviation can greatly reduced the stagnant water effect of stake, leads to higher engineering risk.
The statistical chart of the infiltration flow rate under three different pile position deviations with the maximum pile position deviation angles of 0.5%, 1.0% and 2.0% is shown in fig. 7. It can be seen that as the pile position deviation increases, the resulting seepage rate also increases. When the deviation range is controlled to be 0.5%, the pile position deviation has no influence on the water tightness of the pile group; when the pile position deviation is increased to 1.0%, leakage sometimes occurs, but the flow rate is generally 6 x 10-5m3(ii) less than s; when the pile position deviation is increased to 2.0 percent, leakage is easy to occur, and the analysis shows that the seepage quantity is sensitive to the pile position deviation. Therefore, the pile position deviation is not negligible in the actual and construction process of the project, because the water flow can penetrate the anti-seepage barrier of the pile group, causing serious leakage of the underground water.
In conclusion, the method is simple and easy to implement, fast and convenient, can better simulate the water stopping effect under the design working condition and the actual working condition, obtains the statistical rule, and provides a certain reference value for the design and construction of the engineering.
The method for analyzing the influence of pile position deviation uncertainty on seepage prevention based on Monte Carlo provided by the embodiment of the invention at least comprises the following technical effects:
1. the method is based on actual engineering and combined with a Monte Carlo method to explore the influence of pile position deviation on the anti-seepage effect. And establishing a numerical model to obtain the seepage flow passing through the simulation area based on Darcy's law. The method has reference significance for preventing and remedying the water stop quality accident of the geotechnical engineering, is simple, has strong operability, saves the time, the equipment and other costs, and has the advantages of simple operation, and the like.
2. The method is simple in calculation principle, based on Darcy's law, a certain water head difference is applied to the upper surface and the lower surface of the simulation area, and the seepage flow passing through the simulation area can be obtained through finite element calculation. The algorithm is simple and clear, and is easy to popularize.
3. The random algorithm compiled by the method can realize the randomness of the pile position deviation, can visualize the working conditions possibly occurring in the engineering and has certain guiding significance on the design and construction of the engineering.
Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.
Claims (9)
1. The method for analyzing the influence of pile position deviation uncertainty on seepage prevention based on Monte Carlo is characterized by comprising the following steps of:
step 1, establishing an anti-seepage influence simulation model, and determining input parameters corresponding to the anti-seepage influence simulation model according to working conditions; the input parameters comprise a maximum pile position deviation angle, permeability coefficient information and geometric dimension information;
2, simulating the seepage flow passing through the simulation area by adopting a Monte Carlo method;
and 3, analyzing the influence of pile position deviation on the seepage-proofing effect by taking the seepage flow acquired by simulation as an evaluation index.
2. The method for analyzing the effect of uncertainty in pile position deviation on seepage prevention according to claim 1, wherein the permeability coefficient information comprises the permeability coefficient of the pile, the permeability coefficient of the ground in the simulation area;
the geometric dimension information comprises the number of piles and the dimension information of the piles; the size information of the piles includes diameters of the piles, lengths of the piles, and overlapping lengths between the piles.
3. The method for analyzing the seepage-proofing influence of the Monte Carlo-based pile position deviation uncertainty according to claim 1, wherein in the step 1, the seepage-proofing influence simulation model randomly generates a pile position deviation amount corresponding to each pile by using a random algorithm;
the pile position deviation amount corresponding to each pile is less than or equal to the maximum pile position deviation value, and the maximum pile position deviation value meets the following formula:
dmax＝β×He
in the formula (d)maxRepresents the maximum pile position deviation value, beta represents the maximum pile position deviation angle, HeIndicating the length of the pile.
4. The method of analyzing an impermeable influence of Monte Carlo-based pile position deviation uncertainty according to claim 3, wherein in the impermeable influence simulation model, the top of the pile is set to be free of deviation, the center positions of the bottom of the pile are set to be randomly distributed within a circle having a first diameter, the first diameter being the maximum pile position deviation value.
5. The method of analyzing the effect of Monte Carlo-based pile position uncertainty on seepage prevention according to claim 4, wherein the coordinates (d) of the center of the bottom of the pilex,dy) Expressed as:
dx＝d×cosθ
dy＝d×sinθ
in the formula (d)maxRepresenting the maximum pile position deviation value; rand denotes a random number, rand being [0,1 ]]Uniformly distributing the upper layer; d represents the deviation value of the pile position and satisfies d is less than or equal to dmax(ii) a Theta represents an azimuth angle in polar coordinates generated randomly, and theta is subjected to uniform distribution in [0,2 pi ];
bottom contour of pile (x)z,yz) Expressed as:
xz＝x0+dx×cosα
yz＝y0+dy×sinα
in the formula, x0、y0And (3) representing the horizontal and vertical coordinate values of the axis of the pile under the design condition, wherein alpha represents the azimuth angle under the polar coordinate and belongs to [0,2 pi ].
6. The method for analyzing the seepage prevention influence of the pile position deviation uncertainty based on the Monte Carlo as claimed in claim 1, wherein the step 2, the simulating the seepage flow passing through the simulation area comprises the following sub-steps:
carrying out finite element meshing aiming at the seepage-proofing influence simulation model;
applying a boundary condition to the simulation area based on Darcy's law;
and under the given boundary condition, carrying out finite element solving calculation on the seepage-proofing influence simulation model to obtain the seepage flow passing through the simulation area.
7. The method of analyzing the influence of Monte Carlo-based pile position deviation uncertainty on seepage control according to claim 6, wherein the boundary conditions are: applying a water head difference on the front surface and the rear surface of the simulation area, and setting other surfaces of the simulation area as watertight boundaries;
the seepage flow through the simulation area is expressed as:
ΔQ/Δt＝vA＝kiA
in the formula, Δ Q/Δ t represents the amount of permeation flux passing per unit time, k represents the permeability coefficient, a represents the cross-sectional area orthogonal to the water flow direction, and i represents the hydraulic gradient.
8. The method for analyzing the influence of the uncertainty of the pile position deviation on the seepage prevention according to claim 1, wherein in the step 3, for the input parameters corresponding to a certain working condition, the number of times of seepage of a seepage phenomenon occurring in N Monte Carlo simulations is counted, and the average seepage rate obtained in the N Monte Carlo simulations is counted; analyzing the influence of a certain pile position deviation on the seepage-proofing effect according to the seepage times and the average seepage flow;
comparing the leakage times and the average leakage flow obtained under the input parameters corresponding to different working conditions, and analyzing the influence of different pile position deviations on the anti-seepage effect;
and when the seepage quantity acquired in the simulation is greater than 0, judging that the seepage phenomenon occurs.
9. The method for analyzing the influence of the Monte Carlo-based pile position deviation uncertainty on the seepage prevention according to claim 1, wherein the step 2 further comprises: simulating the distribution information of the simulation area; the distribution information comprises water head distribution information and water flow density distribution information;
the step 3 further comprises: and (4) taking the distribution information acquired by simulation as an auxiliary evaluation index to assist in analyzing the influence of pile position deviation on the anti-seepage effect.
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