Green rotary excavating pile deviation rectifying construction method suitable for inclined hard soil layer

Abstract

The invention discloses a green rotary excavating pile deviation rectifying construction method suitable for an inclined hard soil layer, which comprises the following steps: positioning the center of a pile foundation, and embedding a steel casing based on the center of the pile foundation; drilling equipment is used for drilling, and after the drilling equipment is filled with hard soil, the drilling equipment is lifted to the outside of a drill hole for soil unloading; the hard soil is screened, and the screened hard soil is used for preparing flow-state mixed soil and modified flow-state mixed soil; detecting whether the current stratum is an inclined stratum or not in real time by using an inclination angle sensor on the drilling equipment; when an inclined stratum is detected, the flow-state mixed soil is used for drilling deviation rectification; and the drilled hole is cleaned, and the modified flow-state mixed soil is used for backfilling to form the pile. On the basis, the problem that the perpendicularity of inclined hard soil layer drilling construction is low is solved, and green recycling of engineering spoil resources is achieved.

Description

Technical Field

[0001] This invention relates to the field of bored pile technology, specifically to a green rotary drilling pile correction construction method suitable for inclined hard soil layers. Background Technology

[0002] In recent years, significant progress has been made in the research and optimization of rotary drilling pile construction technology, with numerous technological innovations emerging. This has not only driven the iterative upgrading of construction technology but also significantly improved construction efficiency and project quality. By introducing advanced automated control systems, optimizing drill bit design, and adopting high-strength materials, the adaptability of rotary drilling pile construction to various geological conditions has been significantly enhanced, providing solid technical support for numerous infrastructure construction projects.

[0003] However, despite significant progress, rotary drilling rig construction still faces a series of challenges and problems in practical engineering applications. Particularly when constructing rotary drilling rigs in inclined hard soil layers, the complex and variable geological conditions often pose severe challenges to the construction team. Factors such as hard rock layers, uneven soil distribution, and inclined strata encountered during drilling can easily lead to difficulties in drilling and precise control of pile verticality. This not only seriously delays the construction schedule but may also pose a potential threat to the bearing capacity and stability of the piles, thereby affecting the quality and safety of the entire project.

[0004] Furthermore, the issue of excavated soil generated at the construction site cannot be ignored. As the scale of construction expands, large amounts of excavated soil are continuously transported away from the site. This not only increases transportation costs but may also cause secondary pollution to the surrounding environment if improperly handled, leading to environmental problems such as dust and soil erosion. At the same time, valuable land resources are being wasted without effective utilization, which runs counter to green environmental protection and resource conservation, and urgently requires high attention from both within and outside the industry. Summary of the Invention

[0005] To overcome the problems of drilling difficulties, inaccurate control of pile verticality, and waste of land resources caused by inclined hard soil layers, this invention provides a green rotary drilling pile correction construction method suitable for inclined hard soil layers. By identifying the inclined surface and correcting the deviation through drilling, and recycling the excavated soil, a harmonious balance between construction efficiency, project quality, and environmental protection is achieved.

[0006] According to one aspect of the present invention, the present invention provides a green rotary drilling pile correction construction method suitable for inclined hard soil layers, comprising: locating the center of the pile foundation and embedding a steel casing based on the center of the pile foundation; drilling using drilling equipment, filling the inside of the drilling equipment with hard soil and then lifting the drilling equipment to the outside of the borehole for soil unloading; sieving the hard soil and preparing fluidized mixed soil and modified fluidized mixed soil using the sieved hard soil; using an inclination sensor on the drilling equipment to detect in real time whether the current stratum is inclined; when an inclined stratum is detected, correcting the borehole using the fluidized mixed soil; cleaning the borehole and backfilling it with the modified fluidized mixed soil to form a pile.

[0007] Furthermore, the center of the pile foundation is located, and a steel casing is installed based on the center of the pile foundation, including: locating the center of the pile foundation, excavating at the corresponding position of the center of the pile foundation until a preliminary hole shape is formed, enlarging the preliminary hole shape; aligning the center of the pile foundation with the center of the steel casing, and installing the steel casing downwards, and compacting the soil around the steel casing after completion.

[0008] Further, the hard soil is screened, and the screened hard soil is used to prepare fluidized mixed soil and modified fluidized mixed soil, including: finely screening the hard soil to obtain fine-grained recycled soil and medium-grained recycled soil; thoroughly mixing the fine-grained recycled soil, lime and silicate cement to form a solid binder; thoroughly stirring the solid binder, medium-grained recycled soil and water to form fluidized mixed soil; thoroughly stirring the fluidized mixed soil, sodium hydroxide and polyaluminum chloride to form modified fluidized mixed soil; the sodium hydroxide is used to adjust the pH value of the modified fluidized mixed soil, and the polyaluminum chloride is used to adjust the consistency of the modified fluidized mixed soil.

[0009] Furthermore, the mass of lime in the solid binder is 1 to 1.2 times that of silicate cement, and the mass of fine-grained recycled soil is 4 to 5 times that of lime; the mass of the solid binder in the fluidized bed is 2 to 2.5 times that of water, and the mass of medium-grained recycled soil is 3 to 4 times that of water; the mass of sodium hydroxide in the modified fluidized bed is 1 to 2 times that of polyaluminum chloride, and the mass of the fluidized bed is 25 to 50 times that of polyaluminum chloride; the pH value of the modified fluidized bed is in the range of 7 to 9, and the viscosity is in the range of 15 to 20 Pa·s.

[0010] Furthermore, the tilt sensor on the drilling equipment is used to detect in real time whether the current stratum is inclined. When an inclined stratum is identified, the fluidized mixed soil is used for borehole correction, including: in the initial stage, low-speed drilling is used, and the monitoring results of the tilt sensor on the drilling equipment are used to determine whether the current stratum is inclined; after the drilling is completed in the initial stage and the monitoring results show that the current stratum is not inclined, the drilling speed is changed to medium speed; when the monitoring results show that the current stratum is inclined, the dip angle of the stratum is calculated based on the monitoring results of the GPS positioning system and the tilt sensor, and the backfill height is calculated based on the dip angle; at the same time, drilling is stopped and the drilling equipment is controlled to retract upward to the ground, and then the fluidized mixed soil is extracted and injected into the borehole; after the backfill height is reached and the fluidized mixed soil has completed early solidification, the drilling equipment is used to drill at low speed until the inclined stratum is crossed, and after crossing the inclined stratum, the drilling speed is changed to medium speed.

[0011] Furthermore, determining whether the current formation is an inclined formation based on the monitoring results of the inclination sensor on the drilling equipment includes: calculating the borehole verticality based on the monitoring results of the inclination sensor on the drilling equipment; determining whether the borehole meets the deviation requirement based on the borehole verticality; if the borehole meets the deviation requirement, the current formation is determined to be a non-inclined formation; if the borehole does not meet the deviation requirement, the current formation is determined to be an inclined formation; wherein, the deviation requirement refers to a borehole verticality of less than or equal to 1%.

[0012] Furthermore, the formation dip angle is calculated based on the monitoring results of the GPS positioning system and the tilt sensor, including: obtaining the spatial coordinates of three points on the formation interface based on the monitoring results of the GPS positioning system and the tilt sensor; calculating the normal vector of the formation interface using the spatial coordinates of the three points; and calculating the formation dip angle using the normal vector of the formation interface.

[0013] Furthermore, the backfill height is calculated based on the dip angle of the strata, and the corresponding formula is:

[0014] ,

[0015] in, For backfill height, It is the initial height. The diameter of the borehole. The dip angle of the strata. For the height design coefficient, The calculation formula is:

[0016] ,

[0017] in, This represents the active earth pressure coefficient of the undisturbed soil beneath the inclined section formed by the sloping strata. , The internal friction angle is the angle of friction of the undisturbed soil beneath the inclined section formed by the inclined strata. This is the unit weight of the undisturbed soil beneath the inclined section formed by the sloping strata. The unit weight of the backfill soil, The internal friction angle of the backfill soil.

[0018] Furthermore, when the dip angle of the strata is between 5° and 25°, it is classified as a gently dipping stratum; when the dip angle of the strata is between 25° and 45°, it is classified as a moderately dipping stratum; and when the dip angle of the strata is between 45° and 65°, it is classified as a steeply dipping stratum. The height design coefficient for gently dipping strata is 0 to 0.25, for moderately dipping strata it is 0.25 to 0.5, and for steeply dipping strata it is 0.5 to 1.0.

[0019] Further, the borehole is cleaned and backfilled with the modified fluidized bed soil to form piles, including: after the drilling depth reaches the designed hole depth, cleaning the soil clods and residues at the bottom of the borehole and removing them from the borehole; injecting the modified fluidized bed soil into the borehole until the fine particles and sediments at the bottom of the borehole float up, and then extracting it before the modified fluidized bed soil sets early; after the borehole is cleaned, a steel cage is lowered and the modified fluidized bed soil is backfilled into the borehole for pile foundation grouting; medium-speed backfilling is used for non-inclined strata and low-speed backfilling is used for inclined strata; after the pile foundation is grouted to the top surface, backfilling is stopped, and the steel casing is pulled out before the modified fluidized bed soil sets early, and the gaps are filled with modified fluidized bed soil.

[0020] The above technical solution involves locating the center of the pile foundation, first drilling a hole using drilling equipment, then installing a steel casing and compacting the surrounding soil; installing a GPS positioning system and tilt sensor on the drilling equipment to monitor for significant borehole deviations in real time; screening the excavated hard soil and using it to prepare solid binder, fluidized mixed soil, and modified fluidized mixed soil; when encountering inclined strata, backfilling with a certain height of fluidized mixed soil, allowing it to solidify early, and then drilling at low speed using drilling equipment until the inclined strata are overcome; cleaning the hole using drilling equipment and mud pump, then lowering the reinforcing cage and backfilling with modified fluidized mixed soil, which, after complete solidification, forms a green rotary drilling pile.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) Traditional piling construction techniques are difficult to achieve in inclined strata and have high requirements for site conditions. The piling equipment and methods used in this technique are applicable to exploration drilling in inclined strata with dense structure, high hardness and complex surface.

[0023] (2) When carrying out construction work in inclined strata, the excavated soil is used as raw material for production based on the properties of the excavated soil. This process is to prepare fluidized mixed soil, realize the reuse of solid waste soil, meet the requirements of green and environmentally friendly construction, and reduce construction costs.

[0024] (3) The fluidized soil prepared according to the characteristics of rock and soil has strong fluidity, does not require vibration during construction, and is easy to prepare modified fluidized soil.

[0025] (4) If deviation occurs during the pile driving process, unlike the traditional repeated scanning, backfill with modified fluidized soil, drive the pile again, and repeat the steps until the pile hole meets the verticality requirements.

[0026] (5) The use of GPS positioning system and tilt sensor can achieve accurate control of drill bit position and improve the verticality of drilling. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This invention provides a flowchart of a green rotary drilling pile correction construction method suitable for inclined hard soil layers.

[0029] Figure 2 This is a flowchart of a green rotary drilling pile correction construction method suitable for inclined hard soil layers provided by the present invention.

[0030] Figure 3 This is the first sub-flowchart of a green rotary drilling pile correction construction method suitable for inclined hard soil layers provided by the present invention.

[0031] Figure 4 This is the second sub-flowchart of a green rotary drilling pile correction construction method suitable for inclined hard soil layers provided by the present invention.

[0032] Figure 5 This is the third sub-flowchart of a green rotary drilling pile correction construction method suitable for inclined hard soil layers provided by the present invention.

[0033] Figure 6 This is the fourth sub-flowchart of a green rotary drilling pile correction construction method suitable for inclined hard soil layers provided by the present invention.

[0034] Figure 7 This is the fifth sub-flowchart of a green rotary drilling pile correction construction method suitable for inclined hard soil layers provided by the present invention. Detailed Implementation

[0035] It should be noted that:

[0036] The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover a non-exclusive inclusion, such as a process, method, system, product, or apparatus that includes a series of steps or units, not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0037] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices. The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be decomposed, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined to form new technical solutions. Such combinations are not bound by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0039] Please refer to the appendix. Figures 1 to 2 This invention provides a green rotary drilling pile correction construction method suitable for inclined hard soil layers, the specific steps of which are as follows (including steps S10-S50):

[0040] Step S10: Locate the center of the pile foundation and install the steel casing based on the center of the pile foundation (please refer to the appendix). Figure 3 Step S10 includes steps S101-S102.

[0041] Step S101: Locate the center of the pile foundation, excavate at the corresponding position of the pile foundation center using an excavator until a preliminary hole shape is formed, and enlarge the preliminary hole shape using drilling equipment.

[0042] Step S102: Align the center of the pile foundation with the center of the steel casing, install the steel casing, and compact the soil around the steel casing. The height of the steel casing is 2-3m, and its inner diameter is 0.2-0.4m larger than the diameter of the pile foundation. The steel casing is exposed above the ground for easy removal. In this embodiment, a vibratory hammer is used to install a steel casing with a height of 2.3m and a diameter of 1.2m, with 0.3m of the casing protruding above the ground. Understandably, the installation height, diameter, and height protruding above the ground of the steel casing can be set according to actual needs and are not limited here.

[0043] Step S20: Drilling is carried out using drilling equipment. After the drilling equipment is filled with hard soil, it is lifted to the outside of the borehole to unload the soil.

[0044] In step S20, after the drill bit of the drilling equipment is filled with hard soil, the drill bit is lifted out of the borehole to unload the soil, which is then transported to the first storage pool. In this embodiment, the drilling equipment is a rotary drilling rig.

[0045] Step S30: The hard soil is sieved, and the sieved hard soil is used to prepare fluidized mixed soil and modified fluidized mixed soil.

[0046] In step S30, the fluidized mixed soil is used for borehole correction, and the modified fluidized mixed soil is used for backfilling and pile formation. It should be noted that, compared to existing technologies, the fluidized mixed soil of this invention does not require vibration, eliminating the heavy vibration work and saving significant labor and machinery costs. It also eliminates quality defects such as honeycomb, pitting, and voids caused by insufficient vibration. It can fill every corner of inclined hard soil layers under its own weight, achieving perfect compaction even in densely reinforced and complex-shaped areas, greatly improving construction quality and structural homogeneity. Due to its self-compacting properties, its hardened structure is very dense with low porosity, thus exhibiting better water resistance than ordinary concrete, laying a solid foundation for excellent durability (resistance to freeze-thaw cycles and chloride ion erosion).

[0047] The modified fluidized bed of this invention is a directional enhancement and functional optimization based on fluidized bed, capable of developing early strength at low temperatures. Specifically, by incorporating antifreeze, early-strength agents, and special low-temperature active admixtures, the modified fluidized bed can hydrate normally at -20°C or even lower temperatures, preventing the slurry from freezing and rapidly developing early strength to meet the needs of rapid tunnel repair in cold regions; it maintains low viscosity and high fluidity. In low-temperature environments, the viscosity of ordinary slurry rises sharply, and fluidity is lost. Through compounding, the modified fluidized bed can ensure that the slurry maintains good fluidity and pumpability at low temperatures; it achieves parameterization and modeling of material properties. Furthermore, the properties of the modified fluidized bed (such as setting time, strength development curve, and rheological properties) can be precisely controlled by the mix proportion (such as water-cement ratio, type and dosage of admixtures).

[0048] Please refer to the appendix for details. Figure 4 The following will further describe step S30 (including steps S301-S304).

[0049] Step S301: The hard soil is finely screened to obtain fine-grained recycled soil and medium-grained recycled soil. In this embodiment, the hard soil in the first storage tank is finely screened, wherein hard soil with a particle size of less than 5 mm is used as fine-grained recycled soil, and hard soil with a particle size of more than 5 mm and less than 10 mm is used as medium-grained recycled soil.

[0050] Step S302 involves further crushing the fine-grained recycled soil into powder and thoroughly mixing it with lime and silicate cement to form a solid binder. The mass of lime in the solid binder is 1 to 1.2 times that of the silicate cement, and the mass of the fine-grained recycled soil is 4 to 5 times that of the lime. In this embodiment, the fine-grained recycled soil is further crushed into powder using a roller crusher, and then the fine-grained recycled soil powder, lime, and silicate cement are thoroughly mixed at a mass ratio of 5:1.2:1 to form a solid binder, which is then transported to the second storage tank.

[0051] Step S303: The solid binder, medium-grained recycled soil, and water are thoroughly mixed to form a fluidized mixed soil. The mass of the solid binder in the fluidized mixed soil is 2 to 2.5 times that of the water, and the mass of the medium-grained recycled soil is 3 to 4 times that of the water. In this embodiment, before backfilling the borehole with mud, the solid binder, medium-grained recycled soil, and water are thoroughly mixed at a mass ratio of 2.5:4:1 to form the fluidized mixed soil.

[0052] Step S304: The fluidized bed, sodium hydroxide, and polyaluminum chloride are thoroughly mixed to form a modified fluidized bed. Sodium hydroxide is used to adjust the pH value of the modified fluidized bed, and polyaluminum chloride is used to adjust its consistency. The mass of sodium hydroxide in the modified fluidized bed is 1-2 times that of polyaluminum chloride, and the mass of the fluidized bed is 25-50 times that of polyaluminum chloride. The pH value of the modified fluidized bed ranges from 7 to 9, and its viscosity ranges from 15 to 20 Pa·s. In this embodiment, before backfilling the borehole with mud, the solid binder, sodium hydroxide, and polyaluminum chloride are thoroughly mixed at a mass ratio of 40:2:1 to form a modified fluidized bed with a pH of 7 and a measured viscosity of 17 Pa·s.

[0053] Step S40: Use the tilt sensor on the drilling equipment to detect in real time whether the current stratum is tilted. When tilted stratum is detected, use fluidized mixed soil to correct the borehole deviation.

[0054] In step S40, the inclined strata are divided into gently inclined strata, moderately inclined strata, and steeply inclined strata according to the size of the stratum dip angle. The stratum dip angle refers to the angle between the inclined strata and the horizontal plane.

[0055] Please refer to the appendix for details. Figure 5 The following will further describe step S40 (including steps S401-S404).

[0056] Step S401: In the initial stage, low-speed drilling is adopted, and the monitoring results of the tilt sensor on the drilling equipment are used to determine whether the current formation is an inclined formation.

[0057] In step S401, the borehole verticality is calculated based on the monitoring results of the tilt sensor on the drilling equipment. The borehole verticality is then used to determine whether the borehole meets the deviation requirements. If the borehole meets the deviation requirements, the current formation is determined to be a non-inclined formation; if the borehole does not meet the deviation requirements, the current formation is determined to be an inclined formation. The tilt sensor is used to obtain the borehole inclination angle (i.e., the angle between the borehole and the vertical line of gravity). The borehole verticality is calculated using the borehole inclination angle, using the formula: Borehole Verticality = ;in, This indicates the borehole inclination angle. The deviation requirement refers to a borehole verticality of less than or equal to 1%. That is, when the borehole verticality is less than or equal to 1%, the borehole is considered to meet the deviation requirement, indicating that the current formation is non-inclined. When the borehole verticality is greater than 1%, the borehole is considered to not meet the deviation requirement, indicating that the current formation is inclined. In this embodiment, the initial stage refers to the vertical distance from the bottom of the borehole to the steel casing being less than 2m; low-speed drilling refers to the drilling speed of the drilling equipment being controlled at 1~2m / h.

[0058] Step S402: After the initial drilling stage is completed and the monitoring results show that the current formation is a non-inclined formation, switch to medium-speed drilling. The initial drilling stage is completed when the vertical distance between the bottom of the borehole and the steel casing is greater than or equal to 2m; medium-speed drilling means that the drilling speed of the drilling equipment is controlled at 2~4m / h.

[0059] Step S403: When the monitoring results show that the current stratum is an inclined stratum, the stratum dip angle is calculated based on the monitoring results of the GPS positioning system and the dip angle sensor, and the backfill height is calculated based on the stratum dip angle; at the same time, drilling is stopped and the drilling equipment is controlled to retract upward to the ground, and then the mud pump is used to extract the fluidized mixed soil from the first mixer and inject it into the borehole.

[0060] The following will combine Figure 6 The document further describes the specific steps for calculating the dip angle of the formation based on the monitoring results of the GPS positioning system and the tilt sensor (including steps S4031-4033).

[0061] Step S4031: Obtain the spatial coordinates of three points on the geological interface based on the monitoring results of the GPS positioning system and the tilt sensor. Specifically, first define a global coordinate system, where the x-axis is due east; the y-axis is due north; and the z-axis is vertically downward (the direction of gravity). The three points on the geological interface are then selected as follows: , , , , , Three points on the same stratigraphic interface, among which, The point represents the location of the drill bit, and its coordinates need to be determined by the monitoring results of the GPS positioning system (used to obtain the borehole location) and the tilt sensor. and The coordinates of the point are determined by geological data (i.e. and (The coordinates of the point are known). The following section will further explain how to determine the coordinates based on the monitoring results of the tilt sensor. The specific steps for determining point coordinates.

[0062] 1) The coordinates of the borehole starting point are provided by the GPS positioning system. ,in, This refers to altitude.

[0063] 2) Obtain the measurement depth as place Point sensor data, including hole bevel angle (Angle with the perpendicular line to gravity), azimuth angle (Clockwise angle from due north).

[0064] 3) Calculation Drilling direction vector of the point: In the formula, Indicates the borehole axis at The direction of extension of the point (unit vector). Represents the drilling direction vector Components on the x-axis, Represents the drilling direction vector Components on the y-axis Represents the drilling direction vector The component along the z-axis, express The bevel angle of the hole (i.e., the borehole axis at) (The angle between the direction of the point's extension and the perpendicular line to gravity). express The azimuth of the point (i.e., the clockwise angle in the direction of true north).

[0065] 4) Recursion The coordinates of the point, from the starting point Start by recursively calculating the depth along the trajectory. In this embodiment, the minimum curvature method is used for recursion. The coordinates of the point.

[0066] ① The formula for calculating the change in direction is: In the formula, Indicates the change in full angle; Indicates the previous measurement point The drilling direction vector, ,in, Indicates the previous measurement point The bevel angle of the hole, Indicates the previous measurement point The azimuth angle; Indicates the current measuring point The drilling direction vector of a point.

[0067] ② Calculate the curvature scaling factor using the following formula: In the formula, RF represents the change in the full angle; RF represents the curvature scaling factor.

[0068] ③Calculation The coordinate increment is calculated using the following formula: In the formula, express Point relative to the previous measuring point of Axis coordinate increment; express Point relative to the previous measuring point The increment of the y-axis coordinate; express Point relative to the previous measuring point The z-axis coordinate increment; express Point relative to the previous measurement point The depth increment, express Point relative to the previous measuring point The depth increment can be defined by the user and is not limited here.

[0069] ④ Based on calculation The coordinates of a point are given by the formula: In the formula, Indicates the previous measurement point Spatial coordinates; express Point relative to the previous measurement point The depth increment; Represents the calculated result The coordinates of the point.

[0070] Step S4032: Calculate the normal vector of the formation interface using the spatial coordinates of three points. Specifically, two vectors are constructed using the spatial coordinates of the three points: , Then, the normal vector of the formation interface is calculated using two vectors, using the following formula: In the formula, Let represent the normal vector of the formation interface; ... .

[0071] Step S4033: Calculate the formation dip angle using the normal vector of the formation interface. Specifically, ,in, The normal vector representing the formation interface; Indicates a vertical line; Represents the normal vector The z-axis component. Represents the normal vector with plumb line (i.e., horizontal plane normal) The angle between the strata; the dip angle of the strata. It is a normal vector The angle with the horizontal plane, and the dip angle of the strata Complementary, therefore, the dip angle of the strata .

[0072] Step S404: After the backfill height is reached and the fluidized mixed soil has completed early solidification, use drilling equipment to drill at low speed until you pass through the inclined strata, and then switch to medium speed drilling after passing through the inclined strata.

[0073] In step S404, the backfill height depends on the dip angle of the stratum. The dip angle refers to the angle between the inclined stratum and the horizontal plane, and the initial height is the product of the tangent of the dip angle and the diameter of the pile foundation. Strata with a dip angle between 5° and 25° are considered gently inclined strata, those between 25° and 45° are considered moderately inclined strata, and those between 45° and 65° are considered steeply inclined strata. The ratio of the backfill height to the initial height is defined as the height design coefficient. Preferably, the height design coefficient for gently inclined strata is 0~0.25, for moderately inclined strata it is 0.25~0.5, and for steeply inclined strata it is 0.5~1.0. Early setting refers to a setting time of not less than 2 hours for fluidized soil and modified fluidized soil. The specific formula for calculating the backfill height based on the stratum dip angle will be further introduced below:

[0074] 1) Geometric model

[0075] The borehole in the over-dipping formation is considered to have a diameter of... A cylindrical shape. The inclined strata form a cross-section, dividing the soil within the cylinder into two parts:

[0076] ①Soil 1: The undisturbed soil above the inclined section, with a unit weight of The cohesive force is The internal friction angle is .

[0077] ②Soil 2: The undisturbed soil below the inclined section, with a unit weight of The cohesive force is The internal friction angle is .

[0078] When drilling near inclined strata, a certain amount of soil needs to be backfilled on top of soil body 1, namely fluidized solidified soil (backfill height is...). The bulk density is The cohesive force is The internal friction angle is .

[0079] 2) Mechanical Objectives

[0080] The backfilled fluidized solidified soil must provide sufficient lateral resistance to resist the lateral forces generated by soil 2 in the inclined strata, preventing the drill bit from deviating from the vertical direction during drilling. The lateral forces mainly come from the active earth pressure of soil 2.

[0081] 3) Key Assumptions

[0082] ① Backfill soil has a certain shear strength after early solidification, which can be measured by the equivalent friction coefficient. This indicates the friction between the drilled material and the borehole wall.

[0083] ②The lateral force of soil 2 on the backfill soil is calculated based on the active earth pressure theory, taking into account the dip angle of the strata. .

[0084] ③ The model ignores the influence of soil 1 because soil 1 is located above the inclined section and contributes little to the lateral force of the drill bit. The main focus is on the effect of soil 2.

[0085] 4) Process Derivation

[0086] ① Calculation of lateral forces

[0087] The lateral force exerted by soil mass 2 on the backfill can be expressed as the integral of the active earth pressure over the inclined section. After simplification, the lateral force is related to the effective height (i.e., initial height) of soil mass 2. Related:

[0088] ,

[0089] in, The lateral force exerted by soil mass 2 on the backfill soil. The force is applied to the backfill soil, attempting to push the backfill soil and the drill bit to deviate. The active earth pressure coefficient of soil mass 2. , Let be the internal friction angle of soil 2. Let be the unit weight of soil 2. This is the initial height, representing the vertical height of soil mass 2 within the borehole. , The diameter of the borehole. The dip angle of the strata.

[0090] ② Resistance calculation

[0091] The self-weight of backfill soil Frictional resistance is generated to resist lateral forces:

[0092] ,

[0093] in, For the weight of the backfill soil, The unit weight of the backfill soil, This refers to the backfill height.

[0094] The frictional resistance is:

[0095] ,

[0096] in, The frictional resistance generated by the weight of the backfill soil. The equivalent friction coefficient, The internal friction angle of the backfill soil.

[0097] ③ Equilibrium conditions

[0098] To ensure stability, the frictional resistance must be greater than or equal to the lateral force.

[0099] ,

[0100] Substitute into the expression:

[0101] ,

[0102] The expression for the backfill height is derived as follows:

[0103] .

[0104] ④ Definition of coefficients

[0105] Establish the relationship between backfill height and initial height:

[0106] ,

[0107] in, For height design coefficient.

[0108] Substituting into the above equation, we get:

[0109] ,

[0110] The simplified expression for the height design coefficient is:

[0111] ,

[0112] This means a high design coefficient Should be with Proportional.

[0113] The following examples will be used to calculate the height design coefficients for gently dipping strata (5°~25°, taking 15° and 25°), moderately dipping strata (25°~45°, taking 35° and 45°), and steeply dipping strata (45°~65°, taking 55° and 65°) according to different stratum dip angles.

[0114] Assuming the parameters of the hard soil layer: soil mass 2 internal friction angle bulk density ; Angle of friction of backfill soil bulk density The pile diameter does not need to be defined; it will be canceled out during calculations, so it does not affect the height design factor result.

[0115] Active earth pressure coefficient of soil 2:

[0116] .

[0117] Equivalent friction coefficient of fluidized solidified soil:

[0118] .

[0119] Height design factor:

[0120] .

[0121] (1) Gently dipping strata

[0122] Substitute them separately and The height design coefficients were found to be 0.116 and 0.201, respectively.

[0123] (2) Gently dipping strata

[0124] Substitute them separately and The height design coefficients were found to be 0.302 and 0.432, respectively.

[0125] (3) Steeply dipping strata

[0126] Substitute them separately and The height design coefficients were found to be 0.616 and 0.926, respectively.

[0127] Step S50: Clean the borehole and backfill with modified fluidized soil to form piles. Please refer to the appendix for details. Figure 7 The following will further describe step S50 (including steps S501-S504).

[0128] Step S501: After the drilling depth reaches the designed hole depth, the soil clods and residues at the bottom of the borehole are cleaned up and removed from the borehole. In this embodiment, after reaching the designed hole depth of 10m, the drilling equipment is used to clean up the larger soil clods and residues at the bottom of the borehole and remove them from the borehole.

[0129] Step S502 involves injecting the modified fluidized bed into the borehole until fine particles and sediments at the bottom of the borehole float to the surface, and then extracting it before the modified fluidized bed sets prematurely. Specifically, the modified fluidized bed is pumped from the second mixer using a mud pump and injected into the borehole until smaller fine particles and sediments at the bottom of the borehole float to the surface. The modified fluidized bed is then extracted using a mud pump before the setting time reaches 2 hours.

[0130] Step S503: After the borehole is cleaned, the reinforcing cage is lowered and the modified fluidized soil is backfilled into the borehole for pile foundation grouting. Medium-speed backfilling is used for non-inclined strata, and low-speed backfilling is used for inclined strata. In this embodiment, the backfilling speed for non-inclined strata is 0.4 m / min, and the backfilling speed for inclined strata is 0.2 m / min.

[0131] Step S504: After the pile foundation is poured to the top surface, backfilling is stopped, and the steel casing is pulled out before the modified fluidized soil sets early. The gaps are then filled with modified fluidized soil.

[0132] In summary, this invention provides a green rotary drilling pile correction method suitable for inclined hard soil layers, comprising: locating the pile foundation center; first, drilling a hole using drilling equipment; then, installing a steel casing and compacting the surrounding soil; installing a GPS positioning system and tilt sensor on the drilling equipment to monitor for significant borehole deviation in real time; screening the excavated hard soil and using it to prepare solid binder, fluidized mixed soil, and modified fluidized mixed soil; when encountering inclined strata, backfilling a certain height of fluidized mixed soil, allowing it to solidify early, and then drilling at low speed using drilling equipment until the inclined strata are overcome; cleaning the hole using drilling equipment and a mud pump; after completion, lowering the reinforcing cage and backfilling with modified fluidized mixed soil; and finally, forming a green rotary drilling pile after complete solidification. This invention can solve the problem of low verticality in drilling construction in inclined hard soil layers and achieve the green recycling of engineering waste soil resources.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A green rotary excavated pile deviation correction construction method suitable for inclined hard soil layers, characterized in that, The method comprises the following steps: locating a pile foundation center and burying a steel casing based on the pile foundation center; drilling with a drilling device, lifting the drilling device to the outside of the drill hole after filling the hard soil in the drilling device, and unloading the soil; screening the hard soil and preparing fluid mixed soil and modified fluid mixed soil with the screened hard soil; detecting whether the current stratum is an inclined stratum in real time by using an inclination sensor on the drilling device; when the inclined stratum is detected, using the fluid mixed soil to correct the deviation of the drill hole; cleaning the drill hole and backfilling the modified fluid mixed soil into a pile.

2. The green rotary pile deviation correction construction method for inclined hard soil layers according to claim 1, characterized in that, The method for locating a pile foundation center and burying a steel casing based on the pile foundation center comprises the following steps: locating a pile foundation center, excavating at the position corresponding to the pile foundation center until a hole mouth rudiment is formed, and expanding the hole mouth rudiment; aligning the pile foundation center with the center of the steel casing, burying the steel casing downward, and compacting the soil around the steel casing after completion.

3. The green rotary pile deviation correction construction method for inclined hard soil layers according to claim 1, characterized in that, The method for screening the hard soil and preparing fluid mixed soil and modified fluid mixed soil with the screened hard soil comprises the following steps: finely screening the hard soil to obtain fine-grained regenerated soil and medium-grained regenerated soil; mixing the fine-grained regenerated soil, lime, and Portland cement to form a solid adhesive; thoroughly stirring the solid adhesive, medium-grained regenerated soil, and water to form fluid mixed soil; thoroughly stirring the fluid mixed soil, sodium hydroxide, and polyaluminum chloride to form modified fluid mixed soil; the sodium hydroxide is used to adjust the PH value of the modified fluid mixed soil, and the polyaluminum chloride is used to adjust the consistency of the modified fluid mixed soil.

4. The green rotary pile deviation correction construction method for inclined hard soil layers according to claim 3, characterized in that, The mass of the lime in the solid adhesive is 1-1.2 times that of the Portland cement, and the mass of the fine-grained regenerated soil is 4-5 times that of the lime; the mass of the solid adhesive in the fluid mixed soil is 2-2.5 times that of the water, and the mass of the medium-grained regenerated soil is 3-4 times that of the water; the mass of the sodium hydroxide in the modified fluid mixed soil is 1-2 times that of the polyaluminum chloride, and the mass of the fluid mixed soil is 25-50 times that of the polyaluminum chloride; the PH value of the modified fluid mixed soil ranges from 7 to 9, and the viscosity ranges from 15 to 20 Pa·s.

5. The green rotary pile deviation correction construction method for inclined hard soil layers according to claim 1, characterized in that, The method for detecting whether the current stratum is an inclined stratum in real time by using an inclination sensor on the drilling device and correcting the deviation of the drill hole with the fluid mixed soil when the inclined stratum is identified comprises the following steps: in the initial stage, low-speed drilling is adopted, and the monitoring result of the inclination sensor on the drilling device is used to determine whether the current stratum is an inclined stratum; after the initial stage drilling of the drilling device is completed and the monitoring result shows that the current stratum is a non-inclined stratum, medium-speed drilling is adopted; when the monitoring result shows that the current stratum is an inclined stratum, the stratum inclination is calculated based on the monitoring result of the GPS positioning system and the inclination sensor on the drilling device, the backfilling height is calculated based on the stratum inclination, the drilling is stopped, the drilling device is controlled to retract upward to the ground, the fluid mixed soil is extracted, and the fluid mixed soil is injected into the drill hole; after the backfilling height is reached and the fluid mixed soil is early solidified, low-speed drilling is adopted with the drilling device until the inclined stratum is crossed, and medium-speed drilling is adopted after the inclined stratum is crossed.

6. The green rotary pile deviation correction construction method for inclined hard soil layers according to claim 5, characterized in that, The application relates to a method for determining whether a current stratum is an inclined stratum by combining the monitoring results of an inclination sensor on a drilling device, comprising the following steps: The drilling verticality is calculated by combining the monitoring results of the inclination sensor on the drilling device; Whether the drilling meets the deviation requirement is determined according to the drilling verticality; If the drilling meets the deviation requirement, the current stratum is determined to be a non-inclined stratum, and if the drilling does not meet the deviation requirement, the current stratum is determined to be an inclined stratum; wherein the deviation requirement refers to that the drilling verticality is less than or equal to 1%.

7. The green rotary pile deviation correction construction method for inclined hard soil layers according to claim 5, characterized in that, The stratum inclination is calculated according to the monitoring results of a GPS positioning system and an inclination sensor, comprising the following steps: The spatial coordinates of three points on a stratum interface are obtained based on the monitoring results of the GPS positioning system and the inclination sensor; The normal vector of the stratum interface is calculated by using the spatial coordinates of the three points; The stratum inclination is calculated by using the normal vector of the stratum interface.

8. The green rotary pile deviation correction construction method for inclined hard soil layers according to claim 5, characterized in that, The backfill height is calculated based on the stratum inclination, and the corresponding formula is: ， wherein, is the backfill height, is the initial height, is the diameter of the borehole, is the formation dip angle, is the height design factor, The calculation formula is: ， wherein, Ks is the active earth pressure coefficient of the undisturbed soil under the inclined section formed by the inclined stratum, , φs is the internal friction angle of the undisturbed soil under the inclined section formed by the inclined stratum, γs is the unit weight of the undisturbed soil under the inclined section formed by the inclined stratum, γr is the unit weight of the backfill, φr is the internal friction angle of the backfill.

9. The green rotary pile deviation correction construction method for inclined hard soil layers according to claim 8, characterized in that, When the stratum inclination is between 5 DEG and 25 DEG, the stratum is a gentle inclined stratum; when the stratum inclination is between 25 DEG and 45 DEG, the stratum is a medium inclined stratum; and when the stratum inclination is between 45 DEG and 65 DEG, the stratum is a steep inclined stratum; wherein the height design coefficient of the gentle inclined stratum is 0-0.25, the height design coefficient of the medium inclined stratum is 0.25-0.5, and the height design coefficient of the steep inclined stratum is 0.5-1.

0.

10. The green rotary pile deviation correction construction method for inclined hard soil layers according to claim 1, characterized in that, The drilling is cleaned, and the modified flow state mixed soil is backfilled into a pile, comprising the following steps: After the drilling depth reaches the designed hole depth, the soil blocks and residues at the bottom of the drilling are cleaned and removed from the drilling; The modified flow state mixed soil is poured into the drilling until the fine particles and sediments at the bottom of the drilling float up, and then the modified flow state mixed soil is extracted before early solidification; After the drilling is cleaned, the reinforcement cage is hoisted and placed, the modified flow state mixed soil is backfilled into the drilling to perform pile foundation pouring; wherein the non-inclined stratum adopts medium-speed backfilling, and the inclined stratum adopts low-speed backfilling; After the pile foundation is poured to the top surface, the backfilling is stopped, the steel casing is pulled out before early solidification of the modified flow state mixed soil, and the modified flow state mixed soil is injected into the gap.

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