Method for constructing artificial pile foundation bearing layer on soft soil foundation

Abstract

The present invention provides a method for constructing an artificial pile foundation bearing layer on a soft soil foundation, the method comprising: obtaining the physical and mechanical property parameters of each soil layer in the soft soil foundation; the physical and mechanical property parameters include physical parameters and mechanical parameters; determining the ground load according to the site use properties; inputting the physical and mechanical property parameters of each soil layer in the soft soil foundation and the ground load into a pre-constructed optimal calculation model for an artificial pile foundation bearing layer, obtaining the optimal burial depth, optimal thickness and optimal unconfined compressive strength of the artificial pile foundation bearing layer; inputting the physical parameters into a pre-constructed cementing slurry adaptation processing model, obtaining the formula of the cementing slurry; constructing a construction plan for the artificial pile foundation bearing layer based on the formula of the cementing slurry and the optimal burial depth, optimal thickness and optimal unconfined compressive strength of the artificial pile foundation bearing layer. The method improves construction efficiency, reduces costs, and ensures the safety and reliability of the structure.

Description

Technical Field

[0001] The invention relates to the technical field of soft foundation treatment, in particular to a method for constructing an artificial pile foundation bearing layer on a soft soil foundation. Background Art

[0002] The application of pile foundation in soft soil is a challenging engineering task. The deep characteristics of soft soil foundation, especially in the southeast coastal areas, often make the pile length reach more than 30 meters, or even more than 100 meters. This depth not only increases the physical difficulty of construction, but also significantly increases the economic cost. At the same time, it is also necessary to consider that the hydrological characteristics of soft soil foundation are complex and changeable, which is greatly affected by factors such as seasons and rainfall, which can easily lead to changes in the moisture content of the foundation soil, thereby affecting the bearing capacity and stability of the foundation.

[0003] In actual construction, the low bearing capacity and high compressibility of soft soil foundation make the pile body prone to displacement, affecting the verticality and position accuracy of the pile. The high moisture content in soft soil is not easy to drain, and the pile hole is prone to collapse, which brings great challenges to the pouring of concrete and the quality control of the pile body. These problems not only increase the technical difficulty of the project, but also increase the construction cost and increase the project risk. In addition, the unevenness and poor permeability of soft soil foundation make traditional methods of foundation treatment technologies such as cast-in-place piles and mixing piles prohibitive in terms of cost and construction complexity. These methods often require a large amount of material input and a long construction period.

[0004] Traditional soft soil foundation treatment technology has great limitations, such as unstable treatment effect, high cost, long treatment cycle and environmental influence, which increase the difficulty of soft soil foundation construction. Therefore, soft soil foundation construction requires not only superb engineering technology, but also precise project management and in-depth consideration of environmental factors to ensure the safety, economy and sustainability of the project. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for constructing an artificial pile foundation bearing layer on a soft soil foundation, which improves construction efficiency, reduces costs, and ensures the safety and reliability of the structure. The artificial pile foundation bearing layer can better adapt to different geological conditions, which is an efficient, economical, safe and environmentally friendly soft soil foundation treatment technology.

[0006] In the first aspect, an embodiment of the present invention provides a method for constructing an artificial pile foundation bearing layer on a soft soil foundation, the method comprising: obtaining physical and mechanical property parameters of each soil layer in the soft soil foundation; the physical and mechanical property parameters include physical parameters and mechanical parameters; determining the ground load according to the site usage properties; inputting the physical and mechanical property parameters and the ground load into a pre-constructed optimal calculation model for an artificial pile foundation bearing layer to obtain an optimal burial depth, an optimal thickness and an optimal unconfined compressive strength of a cementing body of the artificial pile foundation bearing layer; inputting the physical parameters into a pre-constructed cementing slurry adaptation processing model to obtain a formula of the cementing slurry; and constructing a construction plan for the artificial pile foundation bearing layer based on the formula of the cementing slurry and the optimal burial depth, optimal thickness and optimal unconfined compressive strength of the cementing body of the artificial pile foundation bearing layer.

[0007] In a preferred embodiment of the present invention, the physical parameters include density, porosity, and natural water content; the mechanical parameters include cohesion, internal friction angle, compression coefficient, compression modulus, and parameters obtained by static penetration test; the parameters obtained by static penetration test include cone head resistance and side wall friction resistance.

[0008] In a preferred embodiment of the present invention, the physical and mechanical property parameters and the ground load are input into a pre-constructed optimal calculation model of an artificial pile foundation bearing layer to obtain the optimal burial depth, optimal thickness and optimal unconfined compressive strength of the cementing body of the artificial pile foundation bearing layer, including: inputting the cohesion, the internal friction angle, the compression coefficient, the compression modulus, the cone head resistance and the side wall friction resistance into a pre-constructed optimal calculation model of an artificial pile foundation bearing layer to obtain the optimal burial depth of the artificial pile foundation bearing layer; inputting the optimal burial depth and the ground load into a pre-constructed optimal calculation model of an artificial pile foundation bearing layer to obtain the optimal thickness of the artificial pile foundation bearing layer; inputting the specific gravity, the natural water content, the compression coefficient, the ground load, the optimal burial depth and the optimal thickness into a pre-constructed optimal calculation model of an artificial pile foundation bearing layer to obtain the optimal unconfined compressive strength of the cementing body of the artificial pile foundation bearing layer.

[0009] In a preferred embodiment of the present invention, the physical parameters are input into a pre-constructed cementing slurry adaptation processing model, including: inputting the density, the porosity and the natural water content into a pre-constructed cementing slurry adaptation processing model to obtain a formula of the cementing slurry.

[0010] In a preferred embodiment of the present invention, the optimal calculation model of the artificial pile foundation bearing layer includes: determining the load acting on the artificial pile foundation bearing layer and the distribution of the load transmitted downward through the artificial pile foundation bearing layer by the load transfer method according to the ground load and soil parameters; then calculating the strain of the soil under the artificial pile foundation bearing layer under the action of load transfer by using the soil compression coefficient and compression modulus; determining the optimal burial depth of the artificial pile foundation bearing layer according to the soil bearing capacity formula; analyzing the distribution of the load in the artificial pile foundation bearing layer by the load balance method to determine the optimal thickness; and calculating the unconfined compressive strength of the cementing body of the artificial pile foundation bearing layer according to the load borne by the artificial pile foundation bearing layer to verify the mechanical properties of the artificial pile foundation bearing layer.

[0011] In a preferred embodiment of the present invention, the bonding slurry adaptation processing model includes: collecting indoor test data of bonding slurries with different formulas on soft soil samples with different density, porosity and natural moisture content; constructing a prediction model based on the indoor test results; the prediction model is a functional relationship between the density, porosity and natural moisture content of the soft soil foundation and the bonding slurry formula; using the collected data to train the model, and after the model training is completed, the model needs to be verified to ensure the accuracy and reliability of its prediction results; and optimizing and adjusting the model based on feedback from actual applications.

[0012] In a preferred embodiment of the present invention, a construction plan for constructing an artificial pile foundation bearing layer is constructed based on the formula of the bonding slurry and the optimal burial depth, optimal thickness and optimal unconfined compressive strength of the artificial pile foundation bearing layer, including: using a high-pressure pipeline in the sea mud rapid consolidation construction machinery and equipment to deliver the bonding slurry to the optimal burial depth, and calculating the pressure and shotcrete spacing of the high-pressure spraying according to the optimal burial depth; calculating the spraying amount of the bonding slurry according to the shotcrete spacing and the optimal thickness of the artificial pile foundation bearing layer; mixing the bonding slurry with the soft soil foundation by high-pressure spraying, so that the soft soil foundation is consolidated by the bonding slurry to form an artificial pile foundation bearing layer; and pile construction can be carried out 28 days after the artificial pile foundation bearing layer is formed.

[0013] In a preferred embodiment of the present invention, the pressure of high-pressure injection and the spraying distance are calculated according to the optimal burial depth, including: the pressure of high-pressure injection ; Spraying spacing ; where h is the optimal burial depth.

[0014] In a preferred embodiment of the present invention, the shotcrete amount of the bonding slurry is calculated according to the shotcrete spacing and the optimal thickness of the artificial pile foundation bearing layer, including: the shotcrete amount M = ; Where D is the optimal thickness.

[0015] In a second aspect, an embodiment of the present invention further provides an artificial pile foundation bearing layer of a soft soil foundation, which is constructed using the method described in the first aspect.

[0016] The embodiments of the present invention bring the following beneficial effects:

[0017] The embodiment of the present invention provides a method for constructing an artificial pile foundation bearing layer on a soft soil foundation, by accurately obtaining the physical and mechanical property parameters of each soil layer of the soft soil foundation and determining the ground load according to the site usage properties, using the optimal calculation model to optimize the design of the artificial pile foundation bearing layer, including the burial depth, thickness and unconfined compressive strength of the cementing body, and combining the cementing slurry adaptation treatment model to accurately match the cementing slurry formula, thereby improving construction efficiency, reducing costs, and ensuring the safety and reliability of the structure. The artificial pile foundation bearing layer can better adapt to different geological conditions, which is an efficient, economical, safe and environmentally friendly soft soil foundation treatment technology.

[0018] To facilitate understanding of this embodiment, firstly, a method for constructing an artificial pile foundation bearing layer on a soft soil foundation disclosed in an embodiment of the present invention is introduced in detail.

[0019] Other features and advantages of the present disclosure will be set forth in the following description, or some features and advantages may be inferred or unambiguously determined from the description, or may be learned by implementing the above-mentioned technology of the present disclosure.

[0020] In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A schematic diagram of a method for constructing an artificial pile foundation bearing layer on a soft soil foundation provided by an embodiment of the present invention;

[0023] Figure 2 A schematic diagram of a specific method for constructing an artificial pile foundation bearing layer on a soft soil foundation provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0025] Hereinafter, the terms "including", "having" and their cognates, which may be used in various embodiments of the present invention, are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or adding the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0026] Soft soil foundations usually refer to soil layers with low bearing capacity, high compressibility, low strength and poor permeability. These soil layers are prone to large settlement or uneven deformation under load. Soft soil foundations usually have the following characteristics:

[0027] High compressibility: The compression coefficient of soft soil foundation is large, which means that under the same pressure, the settlement of soft soil foundation will be much greater than that of hard foundation.

[0028] Low bearing capacity: The vertical load or pressure that a soft soil foundation can withstand per unit area is small, and it is prone to settlement or damage.

[0029] Low strength: Soft soil foundation has low shear strength and is difficult to support large loads, which can easily lead to foundation instability.

[0030] Low permeability: Soft soil foundation has poor permeability and water is not easy to drain out, which will affect the consolidation process and bearing capacity of the foundation.

[0031] Inhomogeneity: The physical and mechanical properties of soft soil foundations may vary greatly in horizontal and vertical directions, resulting in poor uniformity of the foundation.

[0032] Thixotropy: Soft soil foundation has thixotropy, that is, it will deform under the action of external force, and the deformation cannot be completely restored after the external force is removed.

[0033] High moisture content: Soft soil foundations usually contain more water, which affects their density and strength.

[0034] Soft soil foundations are widely distributed around the world, especially in coastal areas, river valleys, lakes and swamps, and some alluvial plains. In engineering construction, the treatment of soft soil foundations is an important issue, and appropriate foundation treatment technologies need to be adopted to improve the bearing capacity and stability of the foundation to ensure the safety and reliability of the project.

[0035] See also Figure 1The embodiment of the present invention provides a method for constructing an artificial pile foundation bearing layer on a soft soil foundation, the method comprising:

[0036] Step S102, obtaining the physical and mechanical property parameters of each soil layer in the soft soil foundation; the physical and mechanical property parameters include physical parameters and mechanical parameters.

[0037] The physical and mechanical parameters of soft soil foundations help to have a deep understanding of the engineering properties of soft soil foundations, and are also the basis for foundation treatment, foundation design, construction plan formulation and prediction of engineering performance. Through accurate measurement and analysis of these parameters, engineering problems that may be caused by soft soil foundations, such as settlement, uneven deformation, stability problems, etc., can be effectively predicted and controlled, thereby ensuring the safety, economy and sustainability of the project.

[0038] Step S104, determining the ground load according to the site usage characteristics.

[0039] Different sites will have different types and sizes of loads depending on their use. For example, industrial areas may have large equipment and heavy machinery, which will generate large static and dynamic loads. Residential areas, on the other hand, have relatively small loads, mainly due to the weight of the building and the activities of residents. The use of the site affects how the load is distributed. In a logistics building or warehouse, the ground load may be unevenly distributed due to racking and stacking, while in a residential or office area, the load distribution may be more even.

[0040] Different site usage characteristics have different requirements for structural design. For example, industrial plants may need to consider concentrated loads generated by large machinery and equipment, while public buildings need to consider loads generated by human flow distribution and activities. The nature of site use determines the size and distribution of ground loads, which directly affects the bearing capacity and deformation of the foundation. When the ground load exceeds the characteristic value of the foundation bearing capacity, special foundation treatment design is required to ensure structural safety.

[0041] Therefore, it is necessary to determine the characteristics, distribution and structural design requirements of the load according to the nature of the site's use.

[0042] Step S106, inputting the physical and mechanical property parameters and the ground load into a pre-constructed optimal calculation model for the artificial pile foundation bearing layer, and obtaining the optimal burial depth, optimal thickness and optimal unconfined compressive strength of the artificial pile foundation bearing layer.

[0043] The optimal burial depth refers to the optimal depth of the bottom surface of the artificial pile foundation bearing layer from the ground. The load is evenly distributed when it is transferred to the artificial pile foundation bearing layer, avoiding settlement and tilting caused by uneven or weak soft soil layers.

[0044] The optimal thickness of the bearing layer of the artificial pile foundation refers to the minimum thickness of the soil layer that directly bears the foundation load in the foundation design to ensure the safety and stability of the structure.

[0045] The optimum unconfined compressive strength of the cementitious body refers to the unconfined compressive strength that the cementitious body of the artificial pile foundation bearing layer should have in order to ensure the stability and safety of the structure during the design and construction process. This parameter is crucial for evaluating the bearing capacity and shear failure resistance of the artificial pile foundation bearing layer.

[0046] Step S108, inputting the physical parameters into a pre-constructed cementing slurry adaptation processing model to obtain a formula of the cementing slurry.

[0047] Cementing slurry is a substance that can bond other materials under physical and chemical action and change from a slurry to a hard substance with a certain strength. The main function of cementing slurry is to improve the strength and integrity of the foundation. After this slurry is injected into soft soil, it will solidify through physical and chemical action to form a cementing body with a tight structure, high strength, good anti-seepage performance and chemical stability, so as to improve the physical and mechanical properties of the cementing object.

[0048] In foundation treatment, cementing slurry is injected, sprayed at high pressure and stirred to bond the slurry with soil particles to improve the physical and mechanical properties of the foundation soil. The use of cementing slurry can enhance the bearing capacity of the soil, reduce settlement and improve the stability of the soil. It is an effective means of strengthening soft soil foundation.

[0049] Step S110, constructing a construction plan for the artificial pile foundation bearing layer based on the formula of the bonding slurry and the optimal burial depth, optimal thickness and optimal unconfined compressive strength of the bonding body of the artificial pile foundation bearing layer.

[0050] The construction plan generally includes the steps of site leveling, measurement and layout, preparation of cementing slurry, transportation of cementing slurry, pouring, high-pressure spraying and stirring.

[0051] The above method comprehensively considers the influence of physical and mechanical property parameters on the bearing layer of the artificial pile foundation, so that the aspects considered in the present invention are more comprehensive and closer to the actual situation, which can improve the safety and economy of the bearing layer of the artificial pile foundation and provide reliable data guarantee for the reconstruction of soft soil foundation.

[0052] Considering that if there are too many physical and mechanical property parameters of soft soil foundation, there will be a certain amount of redundant parameters, which will increase unnecessary calculation amount. Therefore, the above method is simplified according to the physical and mechanical property parameters designed in practical applications and the performance requirements of the bearing layer of artificial pile foundation.

[0053] As a possible implementation, see Figure 2The embodiment of the present invention provides a method for constructing an artificial pile foundation bearing layer on a soft soil foundation, the method comprising:

[0054] Step S202, obtaining the weight, void ratio, natural water content, cohesion, internal friction angle, compression coefficient, compression modulus, cone head resistance and side wall friction resistance of the soft soil foundation; determining the ground load according to the site usage nature.

[0055] The ground load is determined according to the nature of the site use: general building area: number of floors × standard load value (2~2.5kPa), densely populated area: number of floors × standard load value (3.5~4kPa), small vehicle passage load standard value (4kPa), large vehicle passage load standard value (20~35kPa), industrial plant number of floors × standard load value (6~8kPa), design load of the yard, embankment area: height × standard load value (18~20kPa).

[0056] Step S204, inputting the cohesion, the internal friction angle, the compression coefficient, the compression modulus, the cone head resistance and the side wall friction resistance into a pre-constructed optimal calculation model of the artificial pile foundation bearing layer to obtain the optimal burial depth of the artificial pile foundation bearing layer.

[0057] In some implementations of this step, the optimal calculation model of the artificial pile foundation bearing layer includes:

[0058] According to the ground load and soil parameters, the load acting on the artificial pile foundation bearing layer and the distribution of the load transferred downward through the artificial pile foundation bearing layer are determined by the load transfer method;

[0059] Then the soil compression coefficient and compression modulus are used to calculate the strain of the artificial pile foundation bearing layer under load.

[0060] Determine the optimal burial depth of the artificial pile foundation bearing layer according to the soil bearing capacity formula; analyze the distribution of load in the artificial pile foundation bearing layer through the load balance method to determine the optimal thickness;

[0061] According to the load on the bearing layer of the artificial pile foundation, the unconfined compressive strength of the cementing body of the bearing layer of the artificial pile foundation is calculated to verify the mechanical properties of the bearing layer of the artificial pile foundation.

[0062] In a specific implementation of this implementation step, the optimal burial depth , gravity is γ, P is the ground load, q c is the cone resistance of soil and f s Side wall friction, E s is the compression modulus.

[0063] Step S206, inputting the optimal burial depth and the ground load into a pre-constructed optimal calculation model for the artificial pile foundation bearing layer to obtain the optimal thickness of the artificial pile foundation bearing layer.

[0064] In some implementations of this step, there is a positive correlation between the optimal thickness of the artificial pile foundation bearing layer and the optimal embedding depth, and the optimal thickness D=F(h), where h is the optimal embedding depth.

[0065] In a specific implementation, D=d×h, wherein d is a constant with a value ranging from 1 / 3 to 1 / 2.

[0066] Step S208, inputting the specific gravity γ, the natural water content w, the compression coefficient Cc, the ground load P, the optimal burial depth h and the optimal thickness D into a pre-constructed optimal calculation model of the artificial pile foundation bearing layer to obtain the optimal unconfined compressive strength of the cementing body of the artificial pile foundation bearing layer.

[0067] In some embodiments of the present invention, the optimum unconfined compressive strength of the cementitious body is q u = f’ (γ, w, Cc, P, D, h).

[0068] In a specific embodiment, q u =k×P, where k is the comprehensive coefficient (ranging from 5 to 7, selected based on γ, w, Cc, D, and h).

[0069] Step S210, inputting the density, the porosity and the natural water content into a pre-constructed cementing slurry adaptation processing model to obtain a formula of the cementing slurry.

[0070] In some embodiments of this step, the cementing slurry is adapted to the processing model, including:

[0071] Collect indoor test data of different cementing grouts on soft soil samples with different gamma density, void ratio and natural water content;

[0072] According to the indoor test results, a prediction model is constructed; the prediction model is a functional relationship between the weight, porosity and natural water content of the soft soil foundation and the cementing slurry formula;

[0073] Use the collected data to train the model. After the model training is completed, the model needs to be verified to ensure the accuracy and reliability of its prediction results;

[0074] The model is optimized and adjusted based on feedback from actual applications.

[0075] It should be noted that the cementing slurry adaptation treatment model is an empirical model.

[0076] In some embodiments of the present invention, the cementitious slurry adaptation treatment model considers the functional relationship between the weight (γ), porosity (e) and natural water content (w) of the soft soil foundation and the cementitious slurry formula. The following are the specific steps for constructing the model:

[0077] Data collection and preprocessing: Collect indoor test data of different cementing slurries on soft soil samples with different weights, porosity and natural moisture content. These data will serve as the basis for model training.

[0078] Prediction model construction: Use machine learning algorithms, such as XGBoost or WOA-XGBoost hybrid models, to build prediction models. These models are able to process high-dimensional data and provide high prediction accuracy. The input variables of the model include the gravity (γ), porosity (e), and natural water content (w) of the soft soil foundation, and the output variables are the formulation parameters of the cementitious slurry.

[0079] Model training and validation: Use the collected data to train the model. During the training process, you can use cross-validation methods to optimize model parameters and use early stopping techniques to prevent overfitting. After the model training is completed, the model needs to be validated to ensure the accuracy and reliability of its prediction results. You can divide the data set into a training set and a validation set, and use the validation set to evaluate the model performance.

[0080] Model optimization and adjustment: Optimize and adjust the model based on feedback from actual applications.

[0081] Model output: The model will output the appropriate cementitious slurry formula, which will be determined based on the input soft soil foundation parameters (density, porosity and natural water content).

[0082] In some implementations of this embodiment, the cementitious slurry formula includes a cementitious material, an activator, mineral powder and water. The weight ratio of the mineral powder to the cementitious material is 0.4-0.6. The weight ratio of the activator to the cementitious material is 0.02-0.03. The total weight of the cementitious material, the activator and the mineral powder is 1.6-2.5 times the weight of the water.

[0083] Step S212, using the high-pressure pipeline in the sea mud rapid consolidation construction machinery and equipment to send the bonding slurry to the optimal burial depth, and calculate the pressure and spraying spacing of the high-pressure spraying according to the optimal burial depth; calculate the spraying amount of the bonding slurry according to the spraying spacing and the optimal thickness of the artificial pile foundation bearing layer; mix the bonding slurry with the soft soil foundation through high-pressure spraying, so that the soft soil foundation is consolidated by the bonding slurry to form the artificial pile foundation bearing layer; pile construction can be carried out 28 days after the artificial pile foundation bearing layer is formed.

[0084] In some embodiments of step S212, the pressure of the high pressure injection is Associated with the optimal burial depth h .

[0085] In a specific embodiment, the pressure of the high pressure injection = (a + h) MPa; where a is a constant with a value between 15 and 20.

[0086] The shotcrete spacing r is related to the optimal burial depth h In some embodiments, r = (bc × h) m; wherein b and c are both constants. In a specific embodiment, b is between 1.5 and 2.0, and c is between 0.03 and 0.05.

[0087] In some embodiments, the shotcrete amount M is a function of the shotcrete spacing r and the optimal thickness D. Shotcrete amount M = .

[0088] In a specific embodiment, the shotcrete amount of the cementitious slurry is M=π×r 2 ×d×n; n is a constant. The value of n is 0.020~0.035.

[0089] After the 28th day, pile construction was carried out.

[0090] Application Examples

[0091] An artificial pile foundation bearing layer constructed on a soft soil foundation comprises the following steps:

[0092] 1. The preliminary construction of the bridge crossing section was carried out in Ninghai County, Ningbo. The soft soil foundation belongs to the muddy soil of the tidal flat. The engineering staff measured the weight, porosity, natural water content, cohesion, internal friction angle, compression coefficient, compression modulus, cone resistance and side wall friction resistance of the soft soil foundation, among which the cone resistance and side wall friction resistance were obtained through static penetration test.

[0093] The data obtained from the test of the soft soil foundation are as follows:

[0094] Heavy weight: 14.6kN / m 3 ~16.8kN / m 3 , porosity ratio 1.582~2.616, natural water content 57.5%~95.1%, cohesion 6kPa~6.7kPa, internal friction angle 1.4°~1.9°, compression coefficient 1.55~2.76, compression modulus 1.33MPa~1.69MPa, cone head resistance 0.06MPa~0.81MPa and side wall friction resistance 8kPa~9kPa.

[0095] 2. Since the soft soil foundation is used for the embankment of the bridge crossing section, the embankment height is 7m, and the ground load is determined to be 140kN / m 2 .

[0096] 3. In the optimal calculation model of the bearing layer of the artificial pile foundation, input the compression coefficient, compression modulus, cone head resistance and side wall friction resistance. The calculated optimal burial depth is 10m.

[0097] 4. The optimal thickness is based on the formula D=d×h, d is taken as 0.4, and the optimal thickness is 4m.

[0098] 5. According to the calculation function q of the optimal unconfined compressive strength of the cemented body u =k×P ， Where k is the comprehensive coefficient, k is 7, and the output optimal unconfined compressive strength is 1MPa.

[0099] 6. According to the cementing slurry adaptation treatment model, input the density, porosity and natural water content to obtain the cementing slurry formula:

[0100] 45.8 parts of cementitious material, 19.7 parts of mineral powder, 1.3 parts of activator, and 33.2 parts of water.

[0101] The above-mentioned cementing slurries are mixed to form slurry for standby use.

[0102] 7. The cementing slurry is transported to the optimal burial depth of the soft soil foundation through a high-pressure pipeline, and then =25MPa high-pressure spraying makes the cement slurry and soft soil fully mixed, the spraying interval is r=1m, and the spraying amount is controlled at M=π×r 2 ×d×0.035 m 3 , the deep silt soft foundation is quickly consolidated by using cementing slurry to form a high-strength bearing layer, thereby reducing the length of the pile.

[0103] 8. After the 28th day, pile construction is carried out.

[0104] Comparative Example

[0105] This comparative example provides a test process for the buried depth of an artificial pile, and the specific process is as follows:

[0106] In the early stage of the automobile town project in Ninghai County, Ningbo, the soft soil foundation belongs to the muddy soil of the tidal flat. The engineering staff surveyed the depth of the soft soil foundation and tested that the thickness of the soft soil layer was 70m. To ensure the safety of the artificial piles, the single pile compressive bearing capacity was calculated to be 12000kN when the pile was 2m into the rock, which can meet the needs of the project, so the pile burial depth was 72m.

[0107] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for constructing an artificial pile foundation bearing layer on a soft soil foundation, characterized in that: The method comprises: Obtaining the physical and mechanical property parameters of each soil layer in the soft soil foundation; the physical and mechanical property parameters include physical parameters and mechanical parameters; Determine the ground load according to the nature of site use; Inputting the physical and mechanical property parameters and the ground load into a pre-constructed optimal calculation model for the artificial pile foundation bearing layer, and obtaining the optimal burial depth, optimal thickness and optimal unconfined compressive strength of the artificial pile foundation bearing layer; Inputting the physical parameters into a pre-constructed cementing slurry adaptation processing model to obtain a formula of the cementing slurry; A construction scheme for the artificial pile foundation bearing layer is constructed based on the formula of the bonding slurry and the optimal burial depth, optimal thickness and optimal unconfined compressive strength of the bonding body of the artificial pile foundation bearing layer; The optimal calculation model of the artificial pile foundation bearing layer includes: According to the ground load and soil parameters, the load acting on the artificial pile foundation bearing layer and the distribution of the load transferred downward through the artificial pile foundation bearing layer are determined by the load transfer method; Then, the soil compression coefficient and compression modulus are used to calculate the strain of the soil under the artificial pile foundation bearing layer under load transfer; the optimal burial depth of the artificial pile foundation bearing layer is determined according to the soil bearing capacity formula; The load balance method is used to analyze the distribution of load in the bearing layer of the artificial pile foundation and determine the optimal thickness; According to the load on the artificial pile foundation bearing layer, the unconfined compressive strength of the cementing body of the artificial pile foundation bearing layer is calculated to verify the mechanical properties of the artificial pile foundation bearing layer; The bonding slurry adaptation treatment model comprises: Collect indoor test data of different cementing grouts on soft soil samples with different weights, void ratios and natural moisture contents; According to the indoor test data, a prediction model is constructed; the prediction model is a functional relationship between the weight, porosity and natural water content of the soft soil foundation and the cementing slurry formula; Use the collected data to train the model. After the model training is completed, the model needs to be verified to ensure the accuracy and reliability of its prediction results; The model is optimized and adjusted based on feedback from actual applications.

2. The method according to claim 1, characterized in that The physical parameters include gravity, void ratio, and natural water content; The mechanical parameters include cohesion, internal friction angle, compression coefficient, compression modulus and parameters obtained by static penetration test; The parameters obtained by the static penetration test include cone head resistance and side wall friction resistance.

3. The method according to claim 2, characterized in that Inputting the physical and mechanical property parameters and the ground load into a pre-constructed optimal calculation model of the artificial pile foundation bearing layer to obtain the optimal burial depth, optimal thickness and optimal unconfined compressive strength of the artificial pile foundation bearing layer, including: Inputting the cohesion, the internal friction angle, the compression coefficient, the compression modulus, the cone head resistance and the side wall friction resistance into a pre-constructed optimal calculation model for the artificial pile foundation bearing layer to obtain the optimal burial depth of the artificial pile foundation bearing layer; Inputting the optimal burial depth and the ground load into a pre-constructed optimal calculation model for the artificial pile foundation bearing layer to obtain the optimal thickness of the artificial pile foundation bearing layer; The specific gravity, the natural water content, the compression coefficient, the ground load, the optimal burial depth and the optimal thickness are input into a pre-constructed optimal calculation model of the artificial pile foundation bearing layer to obtain the optimal unconfined compressive strength of the cementing body of the artificial pile foundation bearing layer.

4. The method according to claim 2, characterized in that: The physical parameters are input into a pre-built cementitious slurry adaptation processing model, including: The density, the porosity and the natural water content are input into a pre-constructed cementitious slurry adaptation processing model to obtain a formula of the cementitious slurry.

5. The method according to any one of claims 1 to 4, characterized in that: A construction scheme for constructing an artificial pile foundation bearing layer based on the formula of the bonding slurry and the optimal burial depth, optimal thickness and optimal unconfined compressive strength of the bonding body of the artificial pile foundation bearing layer includes: The high-pressure pipeline in the rapid consolidation construction machinery and equipment of the sea mud is used to deliver the cementing slurry to the optimal burial depth, and the pressure and grouting spacing of the high-pressure injection are calculated according to the optimal burial depth; Calculate the shotcrete volume of the cementitious slurry according to the shotcrete spacing and the optimal thickness of the artificial pile foundation bearing layer; The cementing slurry is mixed with the soft soil foundation by high-pressure jetting, so that the soft soil foundation is consolidated by the cementing slurry to form an artificial pile foundation bearing layer; Pile construction can only be carried out 28 days after the artificial pile foundation bearing layer is formed.

6. The method according to claim 5, characterized in that Calculate the pressure and spacing of high-pressure jetting according to the optimal burial depth, including: High pressure injection pressure = (a + h) MPa; where a is a constant, ranging from 15 to 20; Spraying spacing = (bc × h) m; where b is between 1.5 and 2.0, and c is between 0.03 and 0.05; Among them, h is the optimal burial depth.

7. The method according to claim 5, characterized in that Calculate the shotcrete volume of the bonding slurry according to the shotcrete spacing and the optimal thickness of the artificial pile foundation bearing layer, including: Shotcrete volume M= =π×r 2 ×D×n; where n is 0.020~0.035; Among them, D is the optimal thickness.

8. An artificial pile foundation bearing layer for soft soil foundation, characterized in that: The method according to any one of claims 1 to 7 is used to construct the

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