CN117966729A - Construction method of stiff composite pile - Google Patents

Construction method of stiff composite pile Download PDF

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Publication number
CN117966729A
CN117966729A CN202410312980.2A CN202410312980A CN117966729A CN 117966729 A CN117966729 A CN 117966729A CN 202410312980 A CN202410312980 A CN 202410312980A CN 117966729 A CN117966729 A CN 117966729A
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pile
construction
foundation
cement
soil
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王欢
刘荣超
袁圆
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Guangzhou S&y And Civil Engineering Group Co ltd
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Guangzhou S&y And Civil Engineering Group Co ltd
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Abstract

The invention discloses a construction method of a stiff composite pile, which comprises the steps of obtaining the depth of a soft soil foundation of a construction site and judging whether the depth is larger than a preset depth or not; if the foundation is treated by adopting graded preloading; if not, adopting layered replacement to treat the foundation; leveling a construction site, removing barriers, positioning and paying off, and burying a steel pile casing; performing high-pressure rotary cement mixing pile construction, collecting construction parameters of a cement mixing pile in real time, and adaptively adjusting operation parameters of a mixing pile machine by combining a hardness evaluation model; and carrying out prestress pipe pile construction, carrying out bearing capacity test after finishing, namely calculating the first bearing capacity of the stiff composite pile, carrying out pile foundation deflection test if the first bearing capacity is smaller than a preset threshold value, resetting the pile foundation by using a genetic algorithm if the first bearing capacity is deflected, calculating the second bearing capacity, and adjusting the structure of the stirring pile machine to increase the diameter of the cement stirring pile if the second bearing capacity is still smaller than the preset threshold value. According to the invention, through foundation pretreatment, bearing capacity test and pile foundation reset are combined, and pile forming quality is ensured.

Description

Construction method of stiff composite pile
Technical Field
The invention relates to the technical field of pile foundation construction, in particular to a construction method of a stiff composite pile.
Background
The stiff composite pile is a composite carrier, and the compressive strength of the stiff composite pile is improved by combining the cement-soil stirring pile with the prestressed pipe pile. The novel pile body is formed by a cement-soil mixing pile and a prestressed pipe pile together, wherein the cement-soil mixing pile is formed by taking cement as a curing agent, doping additives such as fly ash with an indefinite doping ratio, and then forcibly mixing soft soil and cement by using a mixer.
However, the current construction pile forming rate of the stiff composite pile is not ideal, because the operation parameters of the stirring pile machine are set by manual experience in the construction process, and scientific guidance is lacked; secondly, the flexibility of the current construction process is low, and acceptance and detection are usually carried out after all pile foundations are constructed, and repeated construction is required for pile foundations which fail to be formed, so that the construction period is prolonged, and a large amount of manpower and material resources are consumed.
Disclosure of Invention
In order to solve at least one technical problem set forth above, the present invention provides a construction method of a stiff composite pile, the method comprising:
acquiring the depth of a soft soil foundation of a construction site, and judging whether the depth of the soft soil foundation is larger than a preset depth; if yes, adopting grading preloading to treat the foundation; if not, adopting layering replacement to treat the foundation;
leveling the treated construction site, removing barriers, positioning and paying off, and burying a steel casing;
Performing high-pressure rotary cement-spraying stirring pile construction, collecting construction parameters of a cement stirring pile in real time, and adaptively adjusting operation parameters of a stirring pile machine according to the construction parameters and a hardness evaluation model;
Carrying out construction of a prestressed pipe pile, wherein the prestressed pipe pile is an inner core pile of a cement stirring pile, and carrying out bearing capacity test on a rigid composite pile after construction is finished, and the construction method comprises the following steps:
Calculating a first bearing capacity of the stiff composite pile, and performing pile foundation deflection test when the first bearing capacity is determined to be smaller than a preset threshold value;
When the deviation of the pile foundation is determined, resetting the pile foundation by using a genetic algorithm;
And calculating a second bearing capacity of the reset stiff composite pile, and adjusting the structure of the stirring pile machine when the second bearing capacity is smaller than a preset threshold value so as to increase the diameter of the next cement stirring pile.
In one embodiment, the collecting the construction parameters of the cement mixing pile in real time, analyzing the construction parameters to generate feedback data, and adaptively adjusting the operation parameters of the mixing pile machine by using the feedback data includes:
Collecting construction parameters of the cement mixing pile in real time, wherein the construction parameters comprise motor current, working speed, pressure change rate and construction depth change rate of the mixing pile machine;
inputting the construction parameters into a hardness evaluation model, and outputting the hardness coefficient of the current soil;
and matching the corresponding target parameters of the stirring pile machine according to the hardness coefficient of the current soil property, and controlling the working of the stirring pile machine by utilizing the target parameters.
In one embodiment, the method further comprises training a hardness assessment model, comprising:
acquiring motor current, working speed, pressure change rate, construction depth change and construction depth change rate in the historical construction process of the stirring pile foundation, and taking the motor current, working speed, pressure change rate, construction depth change and construction depth change rate as a training set;
performing feature dimension reduction on the training set by using an SAE algorithm, fitting the dimension-reduced training set, screening out the feature quantity with the largest correlation according to the fitting result, and inputting the feature quantity into a BP neural network for training;
and constructing a loss function according to the mean square error to detect the evaluation precision of the BP neural network, and performing iterative training on the model until the evaluation precision meets the preset condition when the precision does not meet the preset condition, so as to generate a hardness evaluation model.
In one embodiment, the method further comprises:
Determining the construction energy consumption of the mixing pile machine according to the construction parameters of the cement mixing pile;
And optimizing target parameters of the stirring pile machine by using construction energy consumption.
In one embodiment, the resetting operation of pile foundation by genetic algorithm comprises:
Generating a random population by taking horizontal restoring force and the stacking capacity as genes, calculating pile body bending moment of foundation piles corresponding to each population member by adopting a finite difference method, and carrying out iterative optimization based on a genetic algorithm on the condition that the pile body bending moment of the foundation piles does not exceed a control bending moment, so as to output the optimal population member;
and setting horizontal resetting force and stacking capacity of a construction site according to the gene correspondence of the optimal population members so as to drive foundation piles to reset.
In one embodiment, the formula for calculating the bearing capacity of the stiff composite pile comprises:
Quk=2U∑ξsqsli+qk(AjpAp)
Wherein U is the circumference of the pile body of the outer core of the composite pile, ζ s is the side resistance adjustment coefficient of the composite section, q s is the standard value of the side resistance of the cement soil pile of the ith soil layer of the composite section of the stiff composite pile, l i is the thickness of the ith soil layer of the composite section of the stiff composite pile, q k is the standard value of the limiting end resistance, A j is the net area of the pile end of the hollow pile, lambda p is the soil plug effect coefficient, and A p is the sectional area of the pile body of the stiff composite pile.
In one embodiment, the method further comprises:
When the depth of the soft soil foundation is greater than 3m, carrying out grading preloading and obtaining a first parameter; the first parameters comprise a target building load, a total stacking load, a foundation loadable load, a total stacking level and a current stacking level;
judging whether the compactness under the current stacking level reaches the standard compactness or not;
When the compactness under the current stacking level does not reach the standard compactness, the stacking load or stacking time of the remaining stacking level is increased until the standard compactness is reached; and the stacking load of the remaining stacking stage numbers is determined according to the first data.
In one embodiment, the method further comprises:
when the depth of the soft soil foundation is less than or equal to 3m, carrying out layered filling replacement and obtaining second parameters, wherein the second parameters comprise total filler mass, compaction load, total filler layer number and current filler layer number;
Judging whether the compactness under the current filler layer number reaches the standard compactness or not;
and when the compactness under the current number of filler layers does not reach the standard compactness, increasing the compaction load, or increasing the number of total filler layers on the premise of keeping the total filler mass unchanged until the standard compactness is reached.
In one embodiment, the high-pressure rotary cement mixer pile construction comprises:
The wet spraying subsides, a high-pressure rotary spraying stirring pile machine is started, a drill bit drills while rotating, and compressed air is sprayed;
Lifting the drill bit, reversing the ash spraying powder, spraying cement slurry in the lifting process, and stirring to mix soil and cement along the depth direction;
monitoring the lifting height of the drill bit, and stopping cement paste injection when the drill bit is lifted to the distance elevation;
Carrying out cement soil composite stirring, stopping spraying ash powder, and drilling while rotating a drill bit until reaching the elevation of the pile bottom;
and (3) spraying ash powder in a dry mode, lifting the drill bit, and reversely rotating the ash powder to mix cement soil and powder.
In one embodiment, the performing prestressed pipe pile construction includes:
Removing peripheral soil of the cement-soil pile formed after the high-pressure rotary cement-spraying stirring pile is constructed, exposing the outline of the cement-soil pile, and determining the central position of the construction of the prestressed pipe pile according to the exposed cement-soil pile;
the construction is carried out by hammering the prestressed pipe pile, the verticality deviation is not more than 0.5%, the center of the prestressed pipe pile is concentric with the center of the cement soil pile, and the prestressed pipe pile is implanted before the cement soil pile is initially set.
Compared with the prior art, the invention has the beneficial effects that:
1) Before construction, firstly judging the depth of a soft soil foundation of a construction site, and judging whether the depth is larger than a preset depth or not; if yes, adopting grading preloading to treat the foundation; if not, adopting layering replacement to treat the foundation; through different processing modes, the stability of the foundation before construction can be ensured, so that the construction speed is increased, and the construction quality is considered.
2) In the construction process, the high-pressure rotary cement-spraying stirring pile is adopted for construction, the construction parameters of the cement stirring pile are collected in real time, and the hardness of the current soil layer is analyzed by combining the hardness evaluation model, so that the operation parameters of the stirring pile machine can be adaptively adjusted, the accurate control of the stirring pile machine is realized, the stable construction process is ensured, and the pile forming qualification rate of the composite pile is improved.
3) After the current pile foundation construction is finished, the bearing capacity test of the rigid composite pile is carried out, and the method comprises the following steps: calculating a first bearing capacity of the stiff composite pile, and performing pile foundation deflection test when the first bearing capacity is determined to be smaller than a preset threshold value; when the deviation of the pile foundation is determined, resetting the pile foundation by using a genetic algorithm; and calculating a second bearing capacity of the reset stiff composite pile, and adjusting the structure of the stirring pile machine when the second bearing capacity is smaller than a preset threshold value so as to increase the diameter of the cement stirring pile. Through carrying out pile foundation skew test earlier, can combine genetic algorithm to carry out pile foundation and reset when the stake machine takes place the skew, avoided the influence of pile foundation skew, improved the security of pile foundation. In addition, carrying out the bearing capacity test again after resetting, if still not meeting the requirement, then through adjusting the structure of stirring stake machine to the diameter of cement stirring stake when increasing next construction, thereby promote the bearing capacity of pile foundation. Therefore, pile foundation deflection detection and bearing capacity test are adopted, and pile forming quality is greatly improved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.
Drawings
In order to more clearly describe the embodiments of the present invention or the technical solutions in the background art, the following description will describe the drawings that are required to be used in the embodiments of the present invention or the background art.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the technical aspects of the disclosure.
FIG. 1 is a schematic flow chart of a construction method of a stiff composite pile according to an embodiment of the present invention;
Fig. 2 is a flowchart illustrating a sub-step of step S30 in fig. 1 according to an embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The terms first, second and the like in the description and in the claims and in the above-described figures are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.
The term "and/or" is herein merely an association relationship describing an associated object, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the term "at least one" herein means any one of a plurality or any combination of at least two of a plurality, for example, including at least one of A, B, C, may mean including any one or more elements selected from the group consisting of A, B and C.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better illustration of the invention. It will be understood by those skilled in the art that the present invention may be practiced without some of these specific details. In some instances, well known methods, procedures, components, and circuits have not been described in detail so as not to obscure the present invention.
The existing stiff composite pile is low in construction pile forming rate, firstly, setting of operation parameters of a stirring pile machine depends on manual experience, secondly, the flexibility of the construction process is low, and the problems of resource waste, reduction of construction efficiency and the like are easily caused. Therefore, the invention aims to provide a construction method of a stiff composite pile, which can adaptively adjust the operation parameters of a stirring pile machine by detecting soil layer hardness, can detect bearing capacity after one pile foundation is constructed, comprises pile foundation deflection detection, and can reset and re-detect after the deflection occurs, and can adjust the structure of the stirring pile machine if the bearing capacity requirement cannot be met, so that the diameter of a cement stirring pile in the next construction is increased, and the bearing capacity is increased. The pile forming qualification rate can be greatly improved in a step-by-step detection mode, the construction cost is saved, and the construction period is shortened.
Referring to fig. 1, fig. 1 is a schematic flow chart of a construction method of a stiff composite pile according to an embodiment of the invention. As shown in fig. 1, a construction method of a stiff composite pile comprises the following steps:
S10, acquiring the depth of a soft soil foundation of a construction site, and judging whether the depth of the soft soil foundation is larger than a preset depth;
s101, if so, adopting grading preloading to treat the foundation;
s102, if not, adopting layered replacement to treat the foundation.
In one embodiment, the preset depth is set to 3m.
When the depth of the soft soil foundation is greater than 3m, carrying out grading preloading and obtaining a first parameter; the first parameters comprise a target building load, a total stacking load, a foundation loadable load, a total stacking level and a current stacking level;
judging whether the compactness under the current stacking level reaches the standard compactness or not;
When the compactness under the current stacking level does not reach the standard compactness, the stacking load or stacking time of the remaining stacking level is increased until the standard compactness is reached; and the stacking load of the remaining stacking stage numbers is determined according to the first data.
In this embodiment, when the soft soil foundation depth is greater than 3m, the foundation depth is relatively large, and in order to ensure the stability of the foundation, the graded preloading may be performed. And comparing the current compactness with the standard compactness after prepressing, and if the standard compactness is not achieved, increasing the stacking load or the stacking time of the remaining stacking stages, so that the compactness can be increased. And repeating the steps until the standard compactness is achieved.
On the other hand, when the depth of the soft soil foundation is less than or equal to 3m, carrying out layered filling replacement and obtaining second parameters, wherein the second parameters comprise total filler mass, compaction load, total filler layer number and current filler layer number;
Judging whether the compactness under the current filler layer number reaches the standard compactness or not;
and when the compactness under the current number of filler layers does not reach the standard compactness, increasing the compaction load, or increasing the number of total filler layers on the premise of keeping the total filler mass unchanged until the standard compactness is reached.
In this embodiment, if the soft soil foundation depth is smaller than or equal to 3m, the foundation depth is smaller, and in order to ensure the stability of the foundation, the compaction degree of the soil can be increased by layering and changing the filling mode, if the compaction degree under the current filling layer number does not reach the standard compaction degree, the compaction load can be continuously increased, or the total filling layer number can be increased on the premise of keeping the total filling quality unchanged, and thus the compaction degree can reach the standard compaction degree by repeating the operation.
The stability of soil in the foundation is important for the pile foundation construction process, so the foundation is reinforced before the construction. The grading preloading treatment is adopted when the foundation depth is large, and the layering replacement treatment is adopted when the foundation depth is small, so that the stability of the foundation before construction is greatly ensured, the construction speed is accelerated, and the construction quality can be further considered.
S20, leveling the treated construction site, removing obstacles, and carrying out positioning paying-off and steel casing embedding.
Firstly, cleaning and leveling a construction site, and removing obstacles or impurities remained in the construction area. Meanwhile, the construction site can be leveled by using the small road roller, and the compactness of the construction site can be improved after sundries are removed and the site is leveled, so that the normal construction of the site is ensured. If the ditch exists in the area, the water source in the ditch is firstly discharged, and multi-loop construction treatment such as dredging, backfilling and the like is carried out.
And (3) positioning and paying off: the building axis may be determined first and then the pile position and the position of the mixing machine may be determined from the axis, typically with a deviation of no more than 20mm from the axis. In order to avoid deformation in the lateral and vertical directions due to pile pressing, an axis control point and two pile position control points should be arranged at a distance of 30m or more from the pile pressing area. During construction, the control points and positioning points of the axes are required to be rechecked, before the pile position is positioned, whether the distance between the intersection points of the axes is consistent with the pile bitmap is checked, then the instrument is used for measuring the lofting pile through a rectangular coordinate or polar coordinate method, and the distance and the angle are recorded so as to recheck the pile position.
Burying a steel pile casing: the embedded deviation of the pile casing accords with the relevant regulations of the construction standard. For example, after pile foundation positioning, four control piles are set according to the pile position cross nails, and steel pile casings are buried with the four control piles as references. The pile casing is made of a steel plate with a thickness of 5-10 mm, and the top end of the pile casing is higher than the ground by at least 20cm when the pile casing is buried. When the pile casing is buried, the static force of the pile casing is pressed into soil by rotary digging mainly by a drilling machine, the pile casing is kept horizontal, the vertical line at the center of the pile casing is coincident with the center line of the pile, the allowable deviation of the horizontal position is 10cm, and the inclination deviation is not more than 1%.
S30, performing high-pressure rotary cement spraying stirring pile construction, collecting construction parameters of the cement stirring pile in real time, and adaptively adjusting operation parameters of a stirring pile machine according to the construction parameters and a hardness evaluation model;
In one embodiment, a high pressure rotary cement mixer pile construction is performed, comprising:
The wet spraying subsides, a high-pressure rotary spraying stirring pile machine is started, a drill bit drills while rotating, and compressed air is sprayed;
Lifting the drill bit, reversing the ash spraying powder, spraying cement slurry in the lifting process, and stirring to mix soil and cement along the depth direction;
monitoring the lifting height of the drill bit, and stopping cement paste injection when the drill bit is lifted to the distance elevation;
Carrying out cement soil composite stirring, stopping spraying ash powder, and drilling while rotating a drill bit until reaching the elevation of the pile bottom;
and (3) spraying ash powder in a dry mode, lifting the drill bit, and reversely rotating the ash powder to mix cement soil and powder.
Through adopting the construction of high-pressure rotary cement mixer pile, can realize following advantage:
The device has compact structure, small volume, strong maneuverability and small occupied area: the characteristics enable the construction of the high-pressure jet grouting pile to be more flexible, and the construction can be performed in an environment with a small space.
The vibration of the construction machine is very small, and the noise is also low: this means that the high-pressure jet grouting pile is constructed without affecting the surrounding buildings and without generating public hazards such as noise.
The pile body has high cement content and high strength, and is close to a concrete pile: the high-pressure jet grouting pile has great advantages in bearing capacity, and is particularly suitable for being selected under the conditions of limited site conditions and higher bearing capacity.
The adaptability is strong: the high-pressure jet grouting pile is suitable for different types of foundation soil, including sandy soil, silt and the like.
And the construction is flexible: the construction of high-pressure jet grouting piles of different types and sizes can be carried out according to the requirements, and the construction method is suitable for different engineering requirements.
The foundation stability is improved: the high-pressure jet grouting pile can effectively improve the shear strength of the foundation, so that the stability of the foundation is improved.
Referring to fig. 2, in one embodiment, in the construction of a high-pressure rotary cement mixing pile, step S30, collecting construction parameters of the cement mixing pile in real time, analyzing the construction parameters to generate feedback data, and using the feedback data to adaptively adjust operation parameters of the mixing pile machine, includes the following sub-steps:
S301, acquiring construction parameters of a cement mixing pile in real time, wherein the construction parameters comprise motor current, working speed, pressure change rate and construction depth change rate of a mixing pile machine;
S302, inputting the construction parameters into a hardness evaluation model, and outputting the hardness coefficient of the current soil;
s303, matching target parameters of the corresponding stirring pile machine according to the hardness coefficient of the current soil property, and controlling the working of the stirring pile machine by using the target parameters.
The hardness coefficient of the soil can influence the working parameters of the stirring pile machine, and further influence the construction effect and efficiency. Therefore, in this embodiment, it is first required to obtain the construction parameters including the motor current, the working speed, the pressure change rate and the construction depth change rate of the stirring pile machine, and then determine the hardness coefficient of the current soil property according to these parameters in combination with the hardness evaluation model. Specifically, each construction parameter has the following relation with the hardness coefficient of the soil:
Motor current: the magnitude of the motor current directly reflects the workload of the stirring pile machine. Generally, the greater the soil hardness, the greater the motor current required. Because hard soil is more difficult to stir, a greater current is required to drive the stirring stake machine into operation.
Working speed: the working speed determines the working efficiency of the stirring pile machine. For harder soils, it may be desirable to reduce the working speed to ensure the stirring effect. Conversely, for the soil with smaller hardness, the working speed can be properly increased to improve the working efficiency.
Rate of pressure change: the pressure change rate reflects the pressure change condition of the stirring pile machine in the working process. In general, the greater the soil hardness, the greater the rate of change of pressure. This is because hard soil requires more pressure to be effectively stirred.
Construction depth change rate: the construction depth change rate reflects the depth change condition of the stirring pile machine in the construction process. For harder soils, it may be necessary to increase the depth of construction to achieve the desired stirring effect. Conversely, for less hard soils, the depth of construction can be reduced appropriately to save cost and time.
According to the relation, the target parameters of the corresponding stirring pile machine can be matched according to the calculated hardness coefficient of the soil property and the corresponding relation, and the working of the stirring pile machine can be controlled by utilizing the target parameters, so that the construction effect is better.
In one embodiment, training the hardness assessment model based on a neural network algorithm is also required prior to inputting the construction parameters into the hardness assessment model, including:
And acquiring motor current, working speed, pressure change rate, construction depth change and construction depth change rate in the historical construction process of the stirring pile foundation, and taking the motor current, working speed, pressure change rate, construction depth change and construction depth change rate as a training set.
Preferably, data cleaning and normalization operations can be performed after the training set is acquired, so as to improve the quality of the training sample and improve the evaluation accuracy of the model.
Performing feature dimension reduction on the training set by using an SAE algorithm, fitting the dimension-reduced training set, screening out the feature quantity with the largest correlation according to the fitting result, and inputting the feature quantity into a BP neural network for training;
SAE is a deep learning model of unsupervised learning that learns a low-dimensional representation of input data, i.e., feature dimensionality reduction. Specifically, SAE consists of a stack of multiple self-encoders (Autoencoder), each of which is a simple neural network, whose purpose is to learn the compression and decompression process of the input data. In the process, the SAE can capture important characteristics of input data, and discard some unimportant noise information at the same time, so that characteristic dimension reduction is realized.
After feature dimension reduction is carried out, fitting is carried out on the training set after dimension reduction, and feature quantity with the largest correlation is screened out according to fitting results and is input to a BP neural network for training; the BP neural network is a supervised learning neural network, and can gradually adjust own parameters in a forward propagation and backward propagation mode, so that the output of the network is more and more close to a real target variable.
And constructing a loss function according to the mean square error to detect the evaluation precision of the BP neural network, and performing iterative training on the model until the evaluation precision meets the preset condition when the precision does not meet the preset condition, so as to generate a hardness evaluation model.
And finally, constructing a loss function by adopting a mean square error to check the training precision, and adopting the mean square error MSE not only has simple gradient and can train the model faster, but also is sensitive to abnormal values, so that the model training process is more concerned with the true values, and the evaluation precision of the model is improved.
In the construction process, the high-pressure rotary cement-spraying stirring pile is adopted for construction, the construction parameters of the cement stirring pile are collected in real time, the hardness of the current soil layer is analyzed by combining the hardness evaluation model, so that the operation parameters of the stirring pile machine can be adaptively adjusted, the accurate control of the stirring pile machine is realized, the stable operation of the construction process is ensured, and the pile forming qualification rate of the composite pile is also improved.
In a preferred embodiment, after matching the target parameters of the corresponding mixing pile machine, the method further comprises:
Determining the construction energy consumption of the mixing pile machine according to the construction parameters of the cement mixing pile;
And optimizing target parameters of the stirring pile machine by using construction energy consumption.
Specifically, in this embodiment, an energy consumption prediction model may be first established according to historical construction data, so as to predict an energy consumption condition under current construction parameters; and then comparing the predicted energy consumption with a construction standard or historical best practice, and identifying an energy waste point.
According to the comparison analysis result, the target parameters can be adjusted and optimized, including:
Adjusting the stirring speed to reduce energy consumption caused by mechanical friction, and simultaneously adjusting the current of a motor to change the output power and the pressure of a drilling machine;
optimizing the material throwing proportion to reduce the energy required by excessive material treatment;
For higher detected soil humidity and viscosity, it is recommended to reduce the stirring speed or adjust the injection pressure to reduce the additional energy consumption due to the viscous soil.
According to the method, the device and the system, the energy consumption factors are considered, and the target parameters of the stirring pile machine based on the soil hardness coefficient matching can be further optimized, so that the construction effect is enhanced, the equipment energy consumption is reduced, and the construction cost is saved.
S40, performing construction of a prestressed pipe pile, wherein the prestressed pipe pile is an inner core pile of a cement stirring pile, and the bearing capacity of the rigid composite pile is tested after the construction is finished, and the construction method comprises the following steps:
s401, calculating a first bearing capacity of the stiff composite pile, and performing pile foundation deflection test when the first bearing capacity is determined to be smaller than a preset threshold value;
S402, when the deviation of the pile foundation is determined, resetting the pile foundation by using a genetic algorithm;
S403, calculating a second bearing capacity of the reset stiff composite pile, and adjusting the structure of the stirring pile machine when the second bearing capacity is smaller than a preset threshold value so as to increase the diameter of the cement stirring pile.
In one embodiment, a prestressed pipe pile construction is performed, including:
Removing peripheral soil of the cement-soil pile formed after the high-pressure rotary cement-spraying stirring pile is constructed, exposing the outline of the cement-soil pile, and determining the central position of the construction of the prestressed pipe pile according to the exposed cement-soil pile;
the construction is carried out by hammering the prestressed pipe pile, the verticality deviation is not more than 0.5%, the center of the prestressed pipe pile is concentric with the center of the cement soil pile, and the prestressed pipe pile is implanted before the cement soil pile is initially set.
Through inserting the prestressing force tubular pile in the soil cement pile foundation to formed the compound stake of strength nature, through adopting the mode of hammering prestressing force tubular pile, can realize following advantage:
The penetrating ability is strong: the hammering tubular pile is suitable for various cohesive soil and silt, and the hammering tubular pile has better effect when the middle interlayer of thicker sandy soil or the hard interlayer containing more pebble and pebble are required to be penetrated.
The bearing capacity is high: the bearing capacity of hammering tubular pile is higher, can satisfy the bearing demand of most buildings.
The construction cost is lower: compared with other complex construction methods, the hammering tubular pile construction method has the advantages of lower cost and better economic benefit.
The construction speed is high: the construction speed of hammering the pipe pile is higher, and the engineering period can be effectively shortened.
The supervision and detection are convenient: the construction process of hammering the tubular pile is relatively visual, and supervision and detection are more convenient.
After the current composite pile foundation construction is finished, first bearing capacity of the stiff composite pile is calculated, when the first bearing capacity is smaller than a preset threshold value, for example, when the difference between the first bearing capacity and the first bearing capacity is large, pile foundation deflection test is needed, if deflection occurs, reset operation is needed, and safety and bearing performance of the pile foundation are guaranteed.
In one embodiment, a bearing capacity calculation formula for a stiff composite pile is calculated, comprising:
Quk=2Uvξsqsli+qk(AjpAp)
Wherein U is the circumference of the pile body of the outer core of the composite pile, ζ s is the side resistance adjustment coefficient of the composite section, q s is the standard value of the side resistance of the cement soil pile of the ith soil layer of the composite section of the stiff composite pile, l i is the thickness of the ith soil layer of the composite section of the stiff composite pile, q k is the standard value of the limiting end resistance, A j is the net area of the pile end of the hollow pile, lambda p is the soil plug effect coefficient, and A p is the sectional area of the pile body of the stiff composite pile.
Therefore, the bearing capacity of the pile foundation can be rapidly calculated through the formula.
In one embodiment, resetting the pile foundation using a genetic algorithm comprises:
Generating a random population by taking horizontal restoring force and the stacking capacity as genes, calculating pile body bending moment of foundation piles corresponding to each population member by adopting a finite difference method, and carrying out iterative optimization based on a genetic algorithm on the condition that the pile body bending moment of the foundation piles does not exceed a control bending moment, so as to output the optimal population member;
and setting horizontal resetting force and stacking capacity of a construction site according to the gene correspondence of the optimal population members so as to drive foundation piles to reset.
Specifically, the method comprises the following steps:
1) Generating a random population by taking a water sac pressure release value, a horizontal resetting force and/or a stacking amount as genes, and initializing population parameters, wherein the population parameters comprise population scale, variation probability, hybridization proportion and maximum iteration number;
2) Constructing a fitness function:
Wherein F (F 0,ni,Δpj) represents the adaptability of the horizontal reset force of F 0, the stacking capacity of n i and the water sac pressure release value of deltap j; m t、Mmax respectively represents the pile body control bending moment and the pile body maximum bending moment of the foundation pile; u t and u respectively represent the target reset displacement of the pile top and the calculated reset displacement of the pile top; k 1、k2 is an importance coefficient.
3) Selecting parent members of the next generation population according to a roulette algorithm, and generating a child member each time, wherein the probability that the ith member in the parent population is selected is as follows:
Wherein f (x i) is the fitness of the ith member in the parent population, Is the sum of fitness of all members in the parent population, and N is the population scale.
4) Executing the hybridization and mutation processes, iterating to generate a plurality of child members, and terminating the optimization process when the iteration number reaches the maximum iteration number;
5) And calculating the pile body bending moment of the foundation pile corresponding to each group member by adopting a finite difference method, and selecting the member with the largest adaptability in the final generation group as the optimal group member on the condition that the pile body bending moment of the foundation pile does not exceed the control bending moment.
In the embodiment, by adopting genetic algorithm optimization, the global optimal solution can be searched in the solution space, and even if the search space is very large, nonlinear or a plurality of local optimal solutions exist, the situation of sinking in the local optimal solution can be avoided to a certain extent, so that the global searching capability is strong, and meanwhile, the robustness is also strong. Through the pile foundation to the skew resets, ensured that the pile foundation can bear the load of superstructure effectively to ensure the safety and the stability of later stage building itself.
To sum up, this embodiment can carry out bearing capacity test to the stiffening composite pile after current pile foundation construction is finished, includes: calculating a first bearing capacity of the stiff composite pile, and performing pile foundation deflection test when the first bearing capacity is determined to be smaller than a preset threshold value; when the deviation of the pile foundation is determined, resetting the pile foundation by using a genetic algorithm; and calculating a second bearing capacity of the reset stiff composite pile, and adjusting the structure of the stirring pile machine when the second bearing capacity is smaller than a preset threshold value so as to increase the diameter of the cement stirring pile. Through carrying out pile foundation skew test earlier, can combine genetic algorithm to carry out pile foundation and reset when the stake machine takes place the skew, avoided the influence of pile foundation skew, improved the security of pile foundation.
In addition, carrying out the bearing capacity test again after resetting, if still not meeting the requirement, then through adjusting the structure of stirring stake machine to the diameter of cement stirring stake when increasing next construction, thereby promote the bearing capacity of pile foundation. Therefore, pile foundation deflection detection and bearing capacity test of the embodiment greatly improve pile forming quality.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, and are not repeated herein. It will be further apparent to those skilled in the art that the descriptions of the various embodiments of the present invention are provided with emphasis, and that the same or similar parts may not be described in detail in different embodiments for convenience and brevity of description, and thus, parts not described in one embodiment or in detail may be referred to in description of other embodiments.
In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.
In the above embodiments, it may be implemented in whole or in part 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, produces a flow or function in accordance with embodiments of the present invention, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in or transmitted across a computer-readable storage medium. The computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, digital subscriber line (digital subscriber line, DSL)), or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a digital versatile disk (DIGITAL VERSATILEDISC, DVD)), or a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.
Those of ordinary skill in the art will appreciate that implementing all or part of the above-described method embodiments may be accomplished by a computer program to instruct related hardware, the program may be stored in a computer readable storage medium, and the program may include the above-described method embodiments when executed. And the aforementioned storage medium includes: a read-only memory (ROM) or a random-access memory (random access memory, RAM), a magnetic disk or an optical disk, or the like.

Claims (10)

1. A method of constructing a stiff composite pile, the method comprising:
acquiring the depth of a soft soil foundation of a construction site, and judging whether the depth of the soft soil foundation is larger than a preset depth; if yes, adopting grading preloading to treat the foundation; if not, adopting layering replacement to treat the foundation;
leveling the treated construction site, removing barriers, positioning and paying off, and burying a steel casing;
Performing high-pressure rotary cement-spraying stirring pile construction, collecting construction parameters of a cement stirring pile in real time, and adaptively adjusting operation parameters of a stirring pile machine according to the construction parameters and a hardness evaluation model;
Carrying out construction of a prestressed pipe pile, wherein the prestressed pipe pile is an inner core pile of a cement stirring pile, and carrying out bearing capacity test on a rigid composite pile after construction is finished, and the construction method comprises the following steps:
Calculating a first bearing capacity of the stiff composite pile, and performing pile foundation deflection test when the first bearing capacity is determined to be smaller than a preset threshold value;
When the deviation of the pile foundation is determined, resetting the pile foundation by using a genetic algorithm;
And calculating a second bearing capacity of the reset stiff composite pile, and adjusting the structure of the stirring pile machine when the second bearing capacity is smaller than a preset threshold value so as to increase the diameter of the next cement stirring pile.
2. The method for constructing a stiff composite pile according to claim 1, wherein the step of collecting construction parameters of the cement mixing pile in real time, analyzing the construction parameters to generate feedback data, and adaptively adjusting operation parameters of the mixing pile machine by using the feedback data comprises the steps of:
Collecting construction parameters of the cement mixing pile in real time, wherein the construction parameters comprise motor current, working speed, pressure change rate and construction depth change rate of the mixing pile machine;
inputting the construction parameters into a hardness evaluation model, and outputting the hardness coefficient of the current soil;
and matching the corresponding target parameters of the stirring pile machine according to the hardness coefficient of the current soil property, and controlling the working of the stirring pile machine by utilizing the target parameters.
3. The method of constructing a stiff composite pile according to claim 2, further comprising training a stiffness evaluation model, comprising:
acquiring motor current, working speed, pressure change rate, construction depth change and construction depth change rate in the historical construction process of the stirring pile foundation, and taking the motor current, working speed, pressure change rate, construction depth change and construction depth change rate as a training set;
performing feature dimension reduction on the training set by using an SAE algorithm, fitting the dimension-reduced training set, screening out the feature quantity with the largest correlation according to the fitting result, and inputting the feature quantity into a BP neural network for training;
and constructing a loss function according to the mean square error to detect the evaluation precision of the BP neural network, and performing iterative training on the model until the evaluation precision meets the preset condition when the precision does not meet the preset condition, so as to generate a hardness evaluation model.
4. A method of constructing a stiff composite pile according to claim 2, characterised in that the method further comprises:
Determining the construction energy consumption of the mixing pile machine according to the construction parameters of the cement mixing pile;
And optimizing target parameters of the stirring pile machine by using construction energy consumption.
5. The method of constructing a stiff composite pile according to claim 1, wherein the resetting of pile foundations using genetic algorithm comprises:
Generating a random population by taking horizontal restoring force and the stacking capacity as genes, calculating pile body bending moment of foundation piles corresponding to each population member by adopting a finite difference method, and carrying out iterative optimization based on a genetic algorithm on the condition that the pile body bending moment of the foundation piles does not exceed a control bending moment, so as to output the optimal population member;
and setting horizontal resetting force and stacking capacity of a construction site according to the gene correspondence of the optimal population members so as to drive foundation piles to reset.
6. The method of constructing a stiff composite pile according to claim 1, wherein the calculating the bearing capacity calculation formula of the stiff composite pile comprises:
Quk=2U∑ξsqsli+qk(AjpAp)
Wherein U is the circumference of the pile body of the outer core of the composite pile, ζ s is the side resistance adjustment coefficient of the composite section, q s is the standard value of the side resistance of the cement soil pile of the ith soil layer of the composite section of the stiff composite pile, l i is the thickness of the ith soil layer of the composite section of the stiff composite pile, q k is the standard value of the limiting end resistance, A j is the net area of the pile end of the hollow pile, lambda p is the soil plug effect coefficient, and A p is the sectional area of the pile body of the stiff composite pile.
7. A method of constructing a stiff composite pile according to claim 1, characterised in that the method further comprises:
When the depth of the soft soil foundation is greater than 3m, carrying out grading preloading and obtaining a first parameter; the first parameters comprise a target building load, a total stacking load, a foundation loadable load, a total stacking level and a current stacking level;
judging whether the compactness under the current stacking level reaches the standard compactness or not;
When the compactness under the current stacking level does not reach the standard compactness, the stacking load or stacking time of the remaining stacking level is increased until the standard compactness is reached; and the stacking load of the remaining stacking stage numbers is determined according to the first data.
8. A method of constructing a stiff composite pile according to claim 1, characterised in that the method further comprises:
when the depth of the soft soil foundation is less than or equal to 3m, carrying out layered filling replacement and obtaining second parameters, wherein the second parameters comprise total filler mass, compaction load, total filler layer number and current filler layer number;
Judging whether the compactness under the current filler layer number reaches the standard compactness or not;
and when the compactness under the current number of filler layers does not reach the standard compactness, increasing the compaction load, or increasing the number of total filler layers on the premise of keeping the total filler mass unchanged until the standard compactness is reached.
9. The method for constructing a stiff composite pile according to claim 1, wherein the high-pressure rotary cement-spraying stirring pile construction is performed, comprising:
The wet spraying subsides, a high-pressure rotary spraying stirring pile machine is started, a drill bit drills while rotating, and compressed air is sprayed;
Lifting the drill bit, reversing the ash spraying powder, spraying cement slurry in the lifting process, and stirring to mix soil and cement along the depth direction;
monitoring the lifting height of the drill bit, and stopping cement paste injection when the drill bit is lifted to the distance elevation;
Carrying out cement soil composite stirring, stopping spraying ash powder, and drilling while rotating a drill bit until reaching the elevation of the pile bottom;
and (3) spraying ash powder in a dry mode, lifting the drill bit, and reversely rotating the ash powder to mix cement soil and powder.
10. A method of constructing a stiff composite pile according to claim 9, wherein the performing of the pre-stressed pipe pile construction comprises:
Removing peripheral soil of the cement-soil pile formed after the high-pressure rotary cement-spraying stirring pile is constructed, exposing the outline of the cement-soil pile, and determining the central position of the construction of the prestressed pipe pile according to the exposed cement-soil pile;
the construction is carried out by hammering the prestressed pipe pile, the verticality deviation is not more than 0.5%, the center of the prestressed pipe pile is concentric with the center of the cement soil pile, and the prestressed pipe pile is implanted before the cement soil pile is initially set.
CN202410312980.2A 2024-03-19 2024-03-19 Construction method of stiff composite pile Pending CN117966729A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002201638A (en) * 2000-12-28 2002-07-19 Asahi Kasei Corp Soil-cement composite pile and construction method thereof
WO2018184254A1 (en) * 2017-04-07 2018-10-11 东南大学 Carbonization mixing pile-ventilating pipe pile composite foundation and construction method thereof
CN108797571A (en) * 2018-07-09 2018-11-13 江苏地基工程有限公司 A kind of novel stiff composite pile efficient construction method
CN114370073A (en) * 2022-02-11 2022-04-19 浙江坤德创新岩土工程有限公司 Monitoring control system and method for stiffening core composite pile
CN116629125A (en) * 2023-05-26 2023-08-22 中交四航局第一工程有限公司 Whole process data model analysis method for reinforced peat soil
CN117131789A (en) * 2023-10-27 2023-11-28 湖南大学 Deep soft soil area horizontal offset foundation pile resetting system and resetting method

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002201638A (en) * 2000-12-28 2002-07-19 Asahi Kasei Corp Soil-cement composite pile and construction method thereof
WO2018184254A1 (en) * 2017-04-07 2018-10-11 东南大学 Carbonization mixing pile-ventilating pipe pile composite foundation and construction method thereof
CN108797571A (en) * 2018-07-09 2018-11-13 江苏地基工程有限公司 A kind of novel stiff composite pile efficient construction method
CN114370073A (en) * 2022-02-11 2022-04-19 浙江坤德创新岩土工程有限公司 Monitoring control system and method for stiffening core composite pile
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