Building pile foundation pore-forming stability regulation and control method based on mud wall protection capability dynamic feedback
By constructing a set of mud concentration state parameters and mapping them to wall protection capacity state quantities, setting state interval constraints and boundaries, and dynamically controlling mud performance, the problem of insufficient control of mud wall protection capacity in pile foundation drilling construction is solved, and the stability and safety of the drilling process are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-21
- Publication Date
- 2026-03-17
AI Technical Summary
In existing technologies for pile foundation drilling, the control of mud wall protection capacity lacks a dynamic feedback mechanism, making it difficult to provide timely and targeted control paths when adverse changes occur in the wall protection capacity, resulting in insufficient stability and safety in the drilling process.
By constructing a set of mud concentration state parameters, mapping them to wall protection capacity state variables, and setting state interval constraints and boundaries, the evolution path of mud concentration is determined based on the change direction of the wall protection capacity state variables, thereby achieving dynamic control of mud performance.
It achieves dynamic feedback and state-based description of mud wall protection capability, enabling timely adjustment of mud performance, improving the stability and continuity of the pile foundation drilling process, and ensuring that the wall protection capability returns to the stable range.
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Figure CN121675813A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of pile foundation construction technology, specifically to a method for controlling the stability of building pile foundation boreholes based on dynamic feedback of mud wall protection capacity. Background Technology
[0002] During the construction of pile foundations, mud slurry is typically used to maintain the stability of the borehole wall in order to prevent borehole collapse, diameter reduction, and abnormal sedimentation. The mud slurry provides support and isolation to the borehole wall soil through the static pressure generated by its own weight and the additional support formed by its viscosity. As the borehole depth increases and the geological conditions change, the concentration, density, and rheological properties of the mud slurry in the borehole will have a significant impact on the wall protection effect. Therefore, reasonable control of mud slurry properties during pile foundation construction is an important technical aspect to ensure borehole quality and construction safety. In existing pile foundation drilling construction, the control of mud properties mostly relies on ground sampling and testing results, construction experience, or preset parameter ranges. Adjustments to mud concentration, density, and viscosity are usually based on staged or manual judgment. This method can meet the construction requirements under most conventional working conditions, but during the drilling process, when the stratum conditions change or the drilling depth continues to increase, there may be a difference between the actual wall protection state inside the hole and the ground testing results. The change in mud wall protection capacity with the drilling process is difficult to continuously reflect. To improve the safety and stability of the drilling process, related technologies have gradually introduced methods for analyzing the changing trends of drilling parameters to help determine the stability of the borehole wall. However, existing technologies mostly focus on judging a single parameter or static threshold, lacking a control mechanism that systematically correlates changes in mud performance, wall protection capability, and the evolution of the drilling process. This makes it difficult to provide targeted mud control paths in a timely manner when adverse changes occur in wall protection capability, and to feed the control results back to continuously optimize the subsequent drilling process. Therefore, this invention proposes a method for controlling the stability of building pile foundation boreholes based on dynamic feedback of mud wall protection capability. Summary of the Invention
[0003] The purpose of this invention is to provide a method for controlling the stability of building pile foundation drilling based on dynamic feedback of mud wall protection capacity, so as to solve the problems mentioned in the background art.
[0004] This invention can be achieved through the following technical solution: a method for controlling the stability of building pile foundation drilling based on dynamic feedback of mud wall protection capacity, comprising: Step 1: Determine the state determination rules of mud concentration in the hole during the pile foundation drilling process. Establish a correspondence between the mud concentration parameters corresponding to different drilling depths and the corresponding drilling stages, and construct a set of state parameters of mud concentration in the hole during the drilling process based on the correspondence. Step 2: Based on the set of mud concentration state parameters, determine the correspondence between the mud concentration state parameters and the borehole wall support effect, and map the mud concentration state parameters into the wall support capacity state quantity according to the correspondence. Step 3: Based on the changes in the wall protection capacity state quantity during the hole forming process, determine the state interval constraints corresponding to the wall protection capacity state quantity, and determine the state boundary defined by the state interval constraints accordingly. Step 4: When the wall protection capacity state quantity crosses the state boundary and enters the unstable state region, based on the correspondence between the mud concentration state parameters and the wall protection capacity state quantity, determine the mud concentration evolution path that matches the direction of change of the wall protection capacity state quantity, and change the mud concentration state parameters according to the mud concentration evolution path. Step 5: After the mud concentration state parameters change, redetermine the wall protection capacity state variables and their corresponding state interval constraints based on the changed mud concentration state parameters, and apply the redetermined correspondence, state interval constraints and mud concentration evolution path to the determination and change of mud concentration state parameters in subsequent hole forming processes.
[0005] A further technical improvement of the present invention is that: in step one, the determination of the rules for determining the mud concentration state in the borehole includes the following steps: Multiple sampling locations are determined at predetermined depth intervals along the depth direction of the pile hole, and mud concentration detection values are obtained at each sampling location at predetermined time intervals to form a continuous sampling sequence; The continuous sampling sequence is smoothed along the time sequence and along the hole forming axis to generate a continuous state sequence corresponding to the hole forming process. Based on the analysis of the continuous state sequence, the continuous rate of change of the continuous state sequence with the hole forming process and its gradient along the hole forming axis are determined. The mud concentration state parameter set is constructed based on the continuous rate of change and gradient, and the mud concentration state parameter set is associated with the corresponding borehole depth position as the output of the state determination rule.
[0006] A further technical improvement of the present invention is that the step of mapping the mud concentration state parameters to wall protection capacity state quantities based on the mud concentration state parameter set includes the following steps: Obtain mud density and mud viscosity parameters at the corresponding drilling depth location, and associate the mud density and mud viscosity parameters with the corresponding drilling depth location and mud concentration state parameter set; The weight of mud per unit volume is calculated based on the mud density parameter, and the static pressure inside the hole is calculated in combination with the corresponding hole depth position. Based on the mud rheology model, the additional viscous support stress generated by the mud near the borehole wall is calculated based on the gradient parameters in the mud viscosity parameter and mud concentration state parameter set. The static pressure value in the borehole is linearly superimposed with the additional viscous support stress to obtain the equivalent support pressure value. The formation lateral pressure value is calculated based on the formation density parameter at the corresponding drilling depth and the drilling depth. The pressure ratio is calculated based on the equivalent support pressure value and the formation lateral pressure value. The pressure ratio is used as the wall protection capacity state quantity corresponding to the drilling depth.
[0007] A further technical improvement of this invention lies in: when establishing a depth-position matching relationship between the mud density parameter, mud viscosity parameter, and mud concentration state parameter set: Based on the degree of deviation between the sampling depth location corresponding to the mud density parameter and the mud viscosity parameter and the drilling depth location corresponding to the mud concentration state parameter set, the corresponding depth matching reliability parameter is determined. When calculating the equivalent support pressure value based on the mud density and mud viscosity parameters, the depth matching reliability parameter is used as a proportional coefficient to apply to the static pressure value in the borehole or the additional viscous support stress, so that the mud density and mud viscosity parameters corresponding to different depth matching reliability values contribute differently to the equivalent support pressure value.
[0008] A further technical improvement of the present invention lies in the following steps: In step three, the determination of the state interval constraint corresponding to the wall protection capacity state quantity includes the following steps: According to the advancement sequence of the hole forming process, the wall protection capacity state quantity at adjacent hole forming depth positions is obtained, and the change value of the wall protection capacity state quantity is determined by calculating the difference between adjacent wall protection capacity state quantities. Based on the change value, sign consistency judgment is performed on N consecutive change values to determine the change trend parameter of the wall protection capacity state quantity, where N is a predetermined number; Based on the formation category parameters and drilling condition parameters corresponding to the drilling depth, the engineering stability threshold and engineering early warning threshold of the wall protection capacity state quantity are determined. When the wall protection capacity state quantity is less than the engineering early warning threshold and the trend parameter indicates a continuous downward trend, it is determined that the wall protection capacity state quantity has entered the unstable state range. When the wall protection capacity state quantity is not less than the engineering early warning threshold and the trend parameter indicates a continuous upward trend, the wall protection capacity state quantity is determined to exit the unstable state range. Based on the determination results of entering and exiting the unstable state interval, the state boundary defined by the state interval constraint is determined.
[0009] A further technical improvement of the present invention is that: in step four, determining the evolution path of mud concentration includes the following steps: After the wall protection capacity state quantity crosses the state boundary and enters the unstable state region, the change in wall protection capacity state quantity corresponding to a unit change in mud concentration state parameter is determined based on the correspondence between mud concentration state parameter and wall protection capacity state quantity. Based on the deviation of the wall protection capability state quantity from the state boundary, calculate the target wall protection capability state quantity increment required to restore the wall protection capability state quantity to the state boundary. Based on the change in wall protection capacity state quantity corresponding to the change in state quantity of unit mud concentration state parameter, the increment of target wall protection capacity state quantity is converted into the total change of target mud concentration state parameter. Based on the total change of the target mud concentration state parameter, and combined with the positive and negative directions of the total change of the target mud concentration state parameter, the mud concentration evolution path from the current state to the target state is constructed.
[0010] A further technical improvement of the present invention is that: in step four, changing the mud concentration state parameters according to the mud concentration evolution path includes the following steps: After determining the evolution path of mud concentration, the process of changing mud concentration state parameters is divided into multiple continuous adjustment stages; In each adjustment stage, the change in the stage mud concentration state parameter is determined according to the mud concentration evolution path, and the change in the stage mud concentration state parameter is limited to not exceeding a predetermined upper limit. The upper limit of the predetermined variation is determined based on the sensitivity parameter of the formation corresponding to the current drilling depth to changes in mud properties; After each adjustment stage is completed, the mud concentration state parameters are reacquired, and the wall protection capacity state parameters are recalculated based on the correspondence between the mud concentration state parameters and the wall protection capacity state parameters. When the wall protection capacity state quantity is still in the unstable state range, continue to the next adjustment stage. When the wall protection capacity state quantity exits the unstable state range, terminate the change of mud concentration state parameter.
[0011] A further technical improvement of the present invention lies in: in step five, the correspondence between the mud concentration state parameter and the wall protection capacity state quantity is redefined and applied to the subsequent hole forming process, including the following steps: After completing a change in the mud concentration state parameter and causing the wall protection capacity state quantity to exit the unstable state range, the changes in the mud concentration state parameter before and after the change and the corresponding changes in the wall protection capacity state quantity are obtained. Based on the changes in mud concentration state parameters and wall support capacity state parameters, the changes in wall support capacity state parameters corresponding to a unit change in mud concentration state parameters are recalculated and used as the updated correspondence parameters. The updated correspondence parameters are associated with the borehole depth location and formation type parameters, and the original correspondence parameters are replaced. In the subsequent hole-forming process, based on the updated correspondence parameters, the calculation of the wall protection capacity state quantity and the determination of the mud concentration evolution path are re-executed; This allows the changes in mud concentration state parameters during subsequent drilling stages to be based on the updated corresponding parameters, thus achieving adaptive updating of the corresponding relationship as the drilling process progresses.
[0012] Compared with the prior art, the present invention has the following beneficial effects: This invention constructs a set of state parameters that reflect the changes in the state of the mud inside the borehole during the borehole formation process by associating mud concentration parameters with borehole depth and formation stage. Based on this, the mud state parameters are mapped to wall protection capacity state quantities, realizing a state-based description of the wall protection capacity inside the borehole. In this way, the changes in the mud wall protection capacity can be continuously reflected during the borehole formation process, providing a unified state basis for subsequent stability determination and control. Furthermore, this invention sets state range constraints and state boundaries for the wall protection capacity state quantity. When the wall protection capacity state quantity enters an unstable state range, it determines a mud concentration evolution path that matches the direction of wall protection capacity change based on the correspondence between mud state parameters and wall protection capacity state quantity, and adjusts the mud concentration state parameters according to this evolution path. This regulation process, based on state changes, enables mud performance adjustment to have a clear direction and specificity, which helps the wall protection capacity return to the stable range. On the other hand, after adjusting the mud concentration state parameters, this invention further redetermines the correspondence between the mud state parameters and the wall protection capacity state quantity, and applies the updated correspondence to the subsequent hole-forming process, so that the control rules can be dynamically updated with the changes in the hole-forming process and formation conditions. Through the above method, this invention forms a complete control process of determining the cover state, judging stability, executing control and updating feedback, which is conducive to improving the stability and continuity of the pile foundation hole-forming process. Attached Figure Description
[0013] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.
[0014] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation
[0015] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.
[0016] Please see Figure 1 As shown, this invention provides a method for controlling the stability of building pile foundation drilling based on dynamic feedback of mud wall protection capacity, comprising: Step 1: Determine the rules for determining the state of mud concentration in the borehole during pile foundation drilling. Establish a correspondence between mud concentration parameters at different drilling depths and corresponding drilling stages, and construct a set of state parameters for mud concentration during the drilling process based on this correspondence. This step transforms the mud concentration from a single-point, static parameter record into a state-based information foundation that can be continuously updated as the drilling process progresses. By establishing a correspondence between mud concentration parameters at different drilling depths and corresponding drilling stages, the mud concentration parameters acquire a "drilling process context." Furthermore, based on this correspondence, a set of state parameters for mud concentration during the drilling process is constructed, providing a unified data entry point and a consistent state expression basis for subsequent steps to calculate, determine, and control the wall protection capacity.
[0017] The determination of the rules for determining the mud concentration state inside the borehole includes the following steps: Specifically, during the pile foundation drilling process, multiple fixed sampling positions are determined along the depth direction of the pile hole at predetermined depth intervals. For example, multiple sampling positions are determined sequentially at drilling depths of zero meters, one meter, two meters, and up to the target drilling depth, with one meter as the depth interval. At each sampling position, the mud concentration detection value in the hole is continuously acquired at predetermined time intervals, thereby forming a mud concentration detection value sequence arranged in chronological order at each drilling depth position, thus constituting a continuous sampling sequence corresponding to the drilling process.
[0018] After obtaining the continuous sampling sequence, a time-series smoothing process is performed on the mud concentration detection value sequence corresponding to each drilling depth position. This time-series smoothing is used to reduce the impact of instantaneous fluctuations in mud concentration detection values over short periods. For example, by weighted averaging of mud concentration detection values over multiple adjacent time intervals, the mud concentration detection value at that drilling depth position tends to be continuous and stable in the time dimension. After completing the time-series smoothing, without changing the original drilling depth position settings, a hole-axis smoothing process is performed based on the time-series smoothing results corresponding to adjacent drilling depth positions. The hole-axis smoothing process uses the time-series smoothing results of the current drilling depth position and its adjacent drilling depth positions as input, weights and updates the time-series smoothing results corresponding to the current drilling depth position, and writes the weighted result back as the axial smoothing result corresponding to the current drilling depth position. This ensures that the mud concentration detection values at each drilling depth position simultaneously meet the smoothing requirements in both the time and hole-axis dimensions while keeping the drilling depth position unchanged, thereby generating a continuous state sequence corresponding to the drilling process.
[0019] After obtaining the continuous state sequence corresponding to each drilling depth, analysis is performed based on the continuous state sequence to determine the continuous rate of change of the continuous state sequence with the drilling process and the gradient along the drilling axis. The continuous rate of change is obtained by performing a difference calculation on the continuous state sequence values of adjacent time intervals at the same drilling depth position. Specifically, the difference between the continuous state sequence values within adjacent time intervals is divided by the corresponding time interval length, thus characterizing the rate of change of the mud concentration state parameter with time during the drilling process. The gradient along the drilling axis is obtained by performing a difference calculation on the continuous state sequence values at corresponding times at adjacent drilling depth positions. Specifically, the difference between the continuous state sequence values at adjacent drilling depth positions is divided by the corresponding drilling depth interval length, reflecting the changing trend of the mud concentration state parameter along the drilling axis.
[0020] Based on the continuous rate of change and the gradient along the borehole axis, a set of mud concentration state parameters is constructed. The set of mud concentration state parameters is then associated with the corresponding borehole depth positions, so that the set of mud concentration state parameters can reflect the dynamic change characteristics of mud concentration at different borehole depth positions during the borehole formation process. This serves as the output result of the rule for determining the mud concentration state in the borehole, providing basic data support for determining the correspondence between mud concentration state parameters and borehole wall support.
[0021] In one embodiment, during the pile foundation drilling process, multiple fixed sampling positions are determined along the depth direction of the pile hole at predetermined depth intervals. For example, sampling positions with drilling depths of 9 meters, 10 meters, and 11 meters are determined with a depth interval of 1 meter. At each sampling position, the mud concentration detection value in the hole is continuously acquired at predetermined time intervals, thereby forming a mud concentration detection value sequence arranged in chronological order at each drilling depth position.
[0022] Secondly, within the time window corresponding to a certain time point t1, mud concentration detection value sequences are obtained at borehole depths of 9 meters, 10 meters, and 11 meters, respectively. A first set of mud concentration detection value sequences is obtained at a borehole depth of 9 meters, a second set at a borehole depth of 10 meters, and a third set at a borehole depth of 11 meters. Time-series smoothing is then performed on the first, second, and third sets of detection value sequences to obtain the time-series smoothed results corresponding to borehole depths of 9 meters, 10 meters, and 11 meters at time point t1.
[0023] After completing the smoothing process along the time sequence, while keeping the hole depth position unchanged, based on the time sequence smoothing results corresponding to adjacent hole depth positions, smoothing processes along the hole axis are performed on the positions with hole depths of 9 meters, 10 meters and 11 meters respectively, so that the time sequence smoothing result of each hole depth position is updated in combination with the time sequence smoothing results of adjacent hole depth positions, thereby obtaining a continuous state sequence corresponding to the positions with hole depths of 9 meters, 10 meters and 11 meters at time point t1.
[0024] Within the time window corresponding to the next time point t2, following the same sampling method and processing procedure as at time point t1, the corresponding mud concentration detection value sequences are re-acquired at borehole depths of 9 meters, 10 meters, and 11 meters, respectively. Time-series smoothing is then performed on each sequence to obtain the time-series smoothed results at borehole depths of 9 meters, 10 meters, and 11 meters at time point t2. Based on this, the time-series smoothed results at borehole depths of 9 meters, 10 meters, and 11 meters are then smoothed along the borehole axis, thus obtaining the continuous state sequence at borehole depths of 9 meters, 10 meters, and 11 meters at time point t2.
[0025] After obtaining the continuous state sequences corresponding to the drilling depths of 9 meters, 10 meters, and 11 meters at time points t1 and t2, the continuous rate of change of the continuous state sequence at the corresponding drilling depth position with the drilling process is determined based on the difference between the continuous state sequences at the same drilling depth position at time points t1 and t2.
[0026] The gradient of the continuous state sequence along the borehole axis is determined based on the difference between the continuous state sequences at adjacent borehole depths at the same time point.
[0027] Based on the continuous rate of change and the gradient along the borehole axis, a set of mud concentration state parameters is formed. The set of mud concentration state parameters is then associated with the positions at borehole depths of 9 meters, 10 meters, and 11 meters, respectively, as the output result of the rule for determining the mud concentration state in the borehole.
[0028] Step 2: Based on the set of mud concentration state parameters, determine the correspondence between the mud concentration state parameters and the borehole wall support effect, and map the mud concentration state parameters into a state quantity of wall support capacity according to the correspondence. This step establishes a link between the set of mud concentration state parameters and the borehole wall support effect that can be used for subsequent judgment and control, so that subsequent control no longer stops at the direct adjustment of the mud parameters themselves, but is deduced in a correlation with the borehole wall support effect as the target. By determining the correspondence between the mud concentration state parameters and the borehole wall support effect, and mapping the mud concentration state parameters into a state quantity of wall support capacity according to the correspondence, the borehole wall support capacity can be continuously acquired and compared in a unified state quantity form, thus providing a quantifiable basis for determining the subsequent state interval constraints and judging the state boundaries.
[0029] The steps of mapping mud concentration state parameters to wall protection capacity state quantities based on the set of mud concentration state parameters include the following steps: The mud density and viscosity parameters are acquired at the corresponding drilling depth locations, and then correlated with the mud concentration state parameter set according to the corresponding drilling depth locations. Specifically, the mud density and viscosity parameters are acquired by a detection device deployed during the drilling process, and the acquisition depth locations correspond one-to-one with the drilling depth locations corresponding to each state parameter in the mud concentration state parameter set, thereby ensuring the consistency of the spatial location of each parameter in subsequent calculations.
[0030] The weight of the mud per unit volume is calculated based on the mud density parameter, and the static pressure inside the borehole is calculated in conjunction with the corresponding borehole depth. In this embodiment, the weight of the mud per unit volume is determined by multiplying the mud density parameter by the gravitational acceleration, where the gravitational acceleration is taken as 9.81 m / s². The static pressure inside the borehole is obtained by multiplying the weight of the mud per unit volume by the corresponding borehole depth. For example, when the mud density parameter is 1120 kg / m³ and the borehole depth is 20 m, the corresponding static pressure inside the borehole is approximately 220 kPa.
[0031] Based on the mud rheological model, the additional viscous support stress generated by the mud near the borehole wall is calculated using gradient parameters from the mud viscosity parameters and mud concentration state parameters. In this embodiment, the Bingham rheological model is used, which characterizes the rheological behavior of mud under shear stress. Its basic form is that the shear stress is jointly determined by the yield stress term and the plastic viscosity term. The gradient parameter characterizes the degree of change in mud concentration along the borehole axis, corresponding to the shear rate level of the mud near the borehole wall; the mud viscosity parameter participates in the calculation of the additional viscous support stress as a plastic viscosity term. By substituting the gradient parameter into the shear rate term of the Bingham rheological model, the additional viscous support stress generated by the mud near the borehole wall can be calculated.
[0032] The equivalent support pressure value at the corresponding borehole depth is obtained by linearly superimposing the static pressure value inside the borehole with the additional viscous support stress. The equivalent support pressure value is used to comprehensively characterize the borehole wall support capacity formed by the combined effect of the mud's self-weight pressure and the mud flow viscosity effect.
[0033] The lateral pressure value of the formation is calculated based on the formation density parameter at the corresponding borehole depth and the borehole depth itself. The pressure ratio is then calculated based on the equivalent support pressure value and the lateral pressure value of the formation. This pressure ratio is used as the wall protection capacity state quantity corresponding to the borehole depth. In this embodiment, for ease of explanation, the lateral pressure value of the formation is calculated by introducing the at-rest earth pressure coefficient. The lateral pressure value of the formation is equal to the product of the at-rest earth pressure coefficient, the formation density parameter, the gravitational acceleration, and the borehole depth. The at-rest earth pressure coefficient is determined according to the corresponding formation category parameter. Through the pressure ratio, a dimensionless wall protection capacity state quantity can be obtained, which can be used for subsequent determination of state interval constraints and control decisions.
[0034] When establishing a depth-position matching relationship between mud density parameters, mud viscosity parameters, and mud concentration state parameter sets: based on the deviation between the sampling depth positions corresponding to mud density parameters and mud viscosity parameters and the borehole depth positions corresponding to the mud concentration state parameter set, the corresponding depth matching reliability parameter is determined. In a specific embodiment, the mud concentration state parameter set is associated at 1m intervals at borehole depth positions, and the sampling depth positions of mud density parameters and mud viscosity parameters are recorded by the detection device. When the sampling depth position corresponding to mud density parameters and mud viscosity parameters is 20.3m, while the borehole depth position corresponding to the mud concentration state parameter set is 20.0m, the deviation is 0.3m, and the depth matching reliability is determined accordingly. The depth matching reliability parameter is 0.85. When the sampling depth corresponding to the mud density and mud viscosity parameters is 20.8m, and the drilling depth corresponding to the mud concentration state parameter set is 20.0m, the deviation is 0.8m, and the depth matching reliability parameter is determined to be 0.60. When the sampling depth corresponding to the mud density and mud viscosity parameters is 21.0m, and the drilling depth corresponding to the mud concentration state parameter set is 21.0m, the deviation is 0m, and the depth matching reliability parameter is determined to be 1.00. This allows the depth matching reliability parameter to decrease as the deviation increases and reach its maximum value when the deviation is 0m, reflecting the degree of matching between the mud density and mud viscosity parameters in spatial location.
[0035] When calculating the equivalent support pressure based on mud density and viscosity parameters, the depth matching reliability parameter is used as a proportionality coefficient to apply to the borehole static pressure or additional viscous support stress. This ensures that the mud density and viscosity parameters corresponding to different depth matching reliability parameters contribute differently to the equivalent support pressure. After determining the aforementioned depth matching reliability parameter, the borehole static pressure is calculated at a borehole depth of 20.0 m based on the mud density parameter, and the additional viscous support stress is calculated based on the mud viscosity parameter. For example, when the borehole static pressure is 220 kPa and the additional viscous support stress is 30 kPa, if the depth matching reliability parameter is 0.85, then the depth matching reliability parameter is used as a proportionality coefficient to apply to the borehole static pressure, resulting in a value calculated using the proportionality coefficient. The static pressure inside the borehole after the application of the proportional coefficient is 187 kPa. The equivalent support pressure is obtained by linearly superimposing the static pressure after the proportional coefficient is applied with the additional viscous support stress, which is 217 kPa. If the depth matching confidence parameter is 0.60, the static pressure inside the borehole after the proportional coefficient is applied is 132 kPa, which is obtained by linearly superimposing with the additional viscous support stress, which is 162 kPa. If the depth matching confidence parameter is 1.00, the static pressure inside the borehole remains at 220 kPa and is obtained by linearly superimposing with the additional viscous support stress, which is 250 kPa. Thus, the sensitivity of the equivalent support pressure to the deviation between the acquisition depth and the borehole depth is consistently reflected by the depth matching confidence parameter.
[0036] In another specific embodiment, to ensure the selectability of the target of the depth matching reliability parameter for the borehole static pressure value and the additional viscous support stress, the depth matching reliability parameter can also be used as a proportionality coefficient for the additional viscous support stress. For example, when the borehole static pressure value is 220 kPa and the additional viscous support stress is 30 kPa, if the depth matching reliability parameter is 0.85, then the depth matching reliability parameter is used as a proportionality coefficient for the additional viscous support stress, resulting in an additional viscous support stress of 25.5 kPa after the proportionality coefficient is applied. The borehole static pressure value and the additional viscous support stress after the proportionality coefficient are then compared. The equivalent support pressure value obtained by linear superposition is 245.5 kPa. If the depth matching confidence parameter is 0.60, the additional viscous support stress after the proportional coefficient is 18.0 kPa, and the equivalent support pressure value is 238.0 kPa by linear superposition. If the depth matching confidence parameter is 1.00, the additional viscous support stress is kept at 30 kPa and the equivalent support pressure value is 250 kPa by linear superposition. Thus, the depth matching confidence parameter can controllably limit the contribution of the additional viscous support stress to the equivalent support pressure value without changing the calculation process of the borehole static pressure value.
[0037] By following the steps of "determining the corresponding depth matching reliability parameter" and "using the depth matching reliability parameter as a proportional coefficient to apply to the borehole static pressure value or additional viscous support stress", the contribution of mud density parameter and mud viscosity parameter to the calculation of equivalent support pressure value can be distinguished according to the depth matching reliability parameter when there are different degrees of deviation from the mud concentration state parameter set. Thus, even when the borehole depth changes or the parameter acquisition depth shifts, the influence path of the depth position matching relationship between mud density parameter, mud viscosity parameter and mud concentration state parameter set on the calculation of equivalent support pressure value can still be kept consistent.
[0038] Step 3: Based on the changes in the wall protection capacity state quantity during the hole forming process, determine the corresponding state interval constraints, and accordingly determine the state boundaries defined by the state interval constraints. This step further transforms the wall protection capacity state quantity from a "continuously changing state quantity" into a "determinable stability interval system," providing clear judgment criteria and boundary conditions for determining hole formation stability. By determining the corresponding state interval constraints based on the changes in the wall protection capacity state quantity during the hole forming process, and accordingly determining the state boundaries defined by the state interval constraints, subsequent steps can use "whether the state boundary is crossed" as a trigger condition, thus forming a clear judgment entry point and control initiation condition when the wall protection capacity changes from stable to unstable.
[0039] In one specific embodiment, the constraint of the state interval corresponding to the wall protection capability state quantity is determined based on the change of the wall protection capability state quantity during the hole forming process, specifically including the following steps: According to the advancement sequence of the hole forming process, the wall protection capacity state quantity at adjacent hole forming depth positions is obtained, and the change value of the wall protection capacity state quantity is determined by calculating the difference between adjacent wall protection capacity state quantities.
[0040] In this embodiment, the wall protection capability state value is obtained by stepping at a predetermined depth along the drilling depth direction. For example, the wall protection capability state values are obtained as 1.34, 1.29, 1.22 and 1.17 at drilling depth positions of 18 meters, 19 meters, 20 meters and 21 meters respectively. The difference between adjacent wall protection capability state values is -0.05, -0.07 and -0.05 respectively. This forms a sequence of change values consistent with the drilling process advancement sequence, which is used to reflect the direction and magnitude of change of the wall protection capability state value between adjacent drilling depth positions.
[0041] Based on the change value, sign consistency is judged for N consecutive change values to determine the trend parameter of the wall protection capacity state quantity, where N is a predetermined number.
[0042] In this embodiment, N is a positive integer of 3.
[0043] In one specific implementation, N can be set according to the hole-forming advance speed, hole-forming depth interval, and the rate of change of the wall protection capability state quantity, so that the judgment window of the change trend parameter matches the actual evolution rhythm of the hole-forming process.
[0044] After the sequence of changing values is formed, a judgment window is established using N consecutive changing values. The consistency of the signs of each changing value within the judgment window is then assessed. When all N consecutive changing values are negative, the trend parameter indicates that the wall protection capacity is in a continuously decreasing trend; when all N consecutive changing values are positive, the trend parameter indicates that the wall protection capacity is in a continuously increasing trend; and when both positive and negative values exist among the N consecutive changing values, the trend parameter indicates that the wall protection capacity is in a fluctuating state. In this embodiment, N is 3. When three consecutive changing values are -0.05, -0.07, and -0.05, the trend parameter indicates a continuously decreasing trend. By assessing the consistency of the signs of multiple consecutive changing values, the trend parameter reflects the continuous changing trend of the wall protection capacity during the hole-forming process, rather than instantaneous fluctuations.
[0045] Based on the formation category parameters and drilling condition parameters corresponding to the drilling depth, the engineering stability threshold and engineering early warning threshold of the wall protection capacity state quantity are determined.
[0046] After determining the trend parameters, and combining them with the formation category parameters and drilling condition parameters corresponding to the current drilling depth, engineering stability thresholds and engineering warning thresholds that match the formation category and drilling condition are selected. For example, when the formation category parameter indicates silty clay and the drilling condition parameter indicates conventional drilling condition, the engineering stability threshold is determined to be 1.30, and the engineering warning threshold is determined to be 1.10; when the formation category parameter indicates medium sand and the drilling condition parameter indicates disturbed drilling condition, the engineering stability threshold and engineering warning threshold are increased accordingly. Through this method, the engineering stability threshold and engineering warning threshold can be adjusted according to changes in drilling depth and formation conditions to adapt to the wall protection capacity requirements under different formation conditions.
[0047] When the wall protection capacity state quantity is less than the engineering warning threshold and the trend parameter indicates a continuous downward trend, the wall protection capacity state quantity is determined to have entered the unstable state interval; when the wall protection capacity state quantity is not less than the engineering warning threshold and the trend parameter indicates a continuous upward trend, the wall protection capacity state quantity is determined to have exited the unstable state interval; based on the determination results of entering and exiting the unstable state interval, the state boundary defined by the state interval constraint is determined.
[0048] In this embodiment, when the wall protection capability state value is 1.05 and the trend parameter indicates a continuous downward trend, the wall protection capability state value is determined to have entered the unstable state range. After entering the unstable state range, when the wall protection capability state value recovers to 1.12 and the trend parameter indicates a continuous upward trend, the wall protection capability state value is determined to have exited the unstable state range. By separating the determination conditions for entering and exiting the unstable state range, the state range transition of the wall protection capability state value during the hole forming process is simultaneously constrained by both numerical thresholds and trend parameters. This avoids frequent state switching caused by single fluctuations or short-term rebounds, thereby determining the state boundary defined by the state range constraints.
[0049] Step 4: When the wall protection capacity state quantity crosses the state boundary and enters the unstable state region, based on the correspondence between the mud concentration state parameters and the wall protection capacity state quantity, determine the mud concentration evolution path that matches the direction of change of the wall protection capacity state quantity, and change the mud concentration state parameters according to the mud concentration evolution path. This step transforms the state determination result formed in Step 3 into an executable mud concentration control action, ensuring consistency between the triggering conditions, control direction, and control target. By determining the mud concentration evolution path that matches the direction of change of the wall protection capacity state quantity when it crosses the state boundary and enters the unstable state region, the control shifts from "empirical adjustment" to "path-based adjustment based on correspondence," and further changes the mud concentration state parameters according to the mud concentration evolution path, thus providing the wall protection capacity state quantity with a control basis and process path to return to the stable state region.
[0050] Determining the evolution path of mud concentration includes the following steps: In this embodiment, when the wall protection capability state quantity crosses the state boundary and enters the unstable state range during the hole forming process, the process of determining the mud concentration evolution path is executed to guide the mud concentration state parameter to change in a direction that is conducive to restoring hole wall stability.
[0051] Based on the established correspondence between mud concentration state parameters and wall protection capacity state quantities, historical control sample data consistent with the current drilling depth, formation type parameters, and drilling conditions are obtained. Each historical control sample data includes a change in mud concentration state parameters and the corresponding change in wall protection capacity state quantities. The historical control sample data are derived from previous drilling processes or previous drilling processes under the same construction conditions, and are used to reflect the actual impact of changes in mud concentration state parameters on wall protection capacity state quantities under the same conditions.
[0052] In the historical control sample data, the most recent predetermined number of effective control samples are selected, and the ratio of the change in wall protection capacity state quantity to the change in mud concentration state parameter in each effective control sample is calculated. When there are multiple ratios, the comparison values are arithmetically averaged to obtain the change in wall protection capacity state quantity corresponding to the unit change in mud concentration state parameter. The change in wall protection capacity state quantity corresponding to the unit change in mud concentration state parameter is used to characterize the local correspondence between the mud concentration state parameter and the wall protection capacity state quantity at the current drilling depth.
[0053] Based on the deviation of the current wall protection capacity state quantity from the state boundary, and in conjunction with construction safety requirements, a predetermined recovery safety margin is determined on the basis of the state boundary. The change required to restore the wall protection capacity state quantity to the state boundary above the recovery safety margin is determined as the target wall protection capacity state quantity increment. The target wall protection capacity state quantity increment is used to avoid the wall protection capacity state quantity from only restoring to the state boundary and then re-entering the unstable state range due to minor disturbances.
[0054] Based on the increment of the target wall protection capacity state quantity and the change in the wall protection capacity state quantity corresponding to the change in the unit mud concentration state parameter, the total change in the target mud concentration state parameter required to achieve the increment of the target wall protection capacity state quantity is calculated in reverse. Combined with the positive and negative directions of the total change in the target mud concentration state parameter, a mud concentration evolution path is constructed for the change of the mud concentration state parameter from the current state to the target state. The mud concentration evolution path is used to indicate the overall direction and adjustment range of subsequent mud concentration state parameter adjustments.
[0055] Changing the mud concentration state parameters according to the mud concentration evolution path includes the following steps: In this embodiment, when the wall protection capability state quantity crosses the state boundary from a stable state to an unstable state at a certain hole depth, the mud concentration state parameter is changed in stages according to the mud concentration evolution path determined in the aforementioned steps.
[0056] After determining the evolution path of the mud concentration, instead of directly executing the total change of the target mud concentration state parameter all at once, the process of changing the mud concentration state parameter is divided into multiple continuous adjustment stages. The change in mud concentration state parameter corresponding to each adjustment stage does not pre-determine its effect on improving the wall protection capacity; it is only limited by a predetermined upper limit to ensure the stability and controllability of each adjustment process. For example, if the total change of the target mud concentration state parameter is 0.25, and the predetermined upper limit is 0.08, then the change process is divided into four continuous adjustment stages.
[0057] In each adjustment stage, based on the direction of the mud concentration evolution path, the change in the stage mud concentration state parameter is determined, and this change is limited to not exceeding a predetermined upper limit. The predetermined upper limit is determined based on the sensitivity parameter of the formation corresponding to the current borehole depth to changes in mud properties, to avoid excessive fluctuations in mud properties within a short period, which could trigger new instabilities.
[0058] Sensitivity parameters are used to characterize the response sensitivity of the corresponding formation to changes in mud concentration state parameters during borehole construction and its ability to withstand construction disturbances. They reflect the strength of the influence of changes in mud concentration state parameters on borehole wall stability.
[0059] The sensitivity parameters are preset based on the formation type parameters corresponding to the current borehole depth, and can be adjusted by combining the actual control effects during previous borehole construction processes. For strata with poor self-stability, loose structure, and sensitivity to construction disturbance, such as loose sand or gravel layers, a higher sensitivity parameter is set, preferably ranging from 0.8 to 1.0, to correspond to a more conservative upper limit of the predetermined variation, thereby limiting the variation range of mud concentration state parameters within a single adjustment stage. For strata with good self-stability, intact structure, and insensitivity to construction disturbance, such as cohesive soil layers, a low sensitivity parameter is set, preferably ranging from 0.4 to 0.6, while allowing a relatively large upper limit of predetermined variation under the premise of ensuring construction safety. By introducing a sensitivity parameter, the predetermined upper limit of variation can be adaptively adjusted according to different drilling depths, locations, and formation conditions. This allows for the simultaneous consideration of the stability of the control process and the requirements for borehole wall stability during the phased change of mud concentration state parameters.
[0060] After each adjustment stage is completed, the mud concentration state parameters at the current drilling depth are reacquired, and the wall-wall capacity state parameters are recalculated based on the correspondence between the mud concentration state parameters and the wall-wall capacity state parameters. This recalculation process does not assume the magnitude of change in the wall-wall capacity state parameters, but uses the actual calculation results as the basis for subsequent judgments. For example, if the total change in the target mud concentration state parameters is 0.25 and it is divided into 4 consecutive adjustment stages, the change in mud concentration state parameters for each adjustment stage is approximately 0.0625. Based on the change in wall-wall capacity state parameters corresponding to a unit change in mud concentration state parameters at the current drilling depth being 0.4, after the first adjustment stage is completed, the wall-wall capacity state parameters are recalculated from 1.05 to approximately 1.075. After the second adjustment stage is completed, the wall-wall capacity state parameters are recalculated from approximately 1.075 to approximately 1.10. The recalculation results are used as the basis for determining whether to continue with the next adjustment stage.
[0061] Based on the relationship between the recalculated wall protection capacity state quantity and the engineering warning threshold, it is determined whether to continue to the next adjustment stage. When the wall protection capacity state quantity is still in the unstable state range, the next adjustment stage continues; when the wall protection capacity state quantity exits the unstable state range and reaches a wall protection capacity state quantity higher than the engineering warning threshold, the change of mud concentration state parameter is terminated, thereby completing the stability control at the current borehole depth.
[0062] Step 5: After the mud concentration state parameters change, the wall protection capacity state variables and their corresponding state interval constraints are redefined based on the changed mud concentration state parameters. The redefined correspondences, state interval constraints, and mud concentration evolution paths are then applied to the determination and modification of mud concentration state parameters during subsequent drilling processes. This step uses the control results from Step 4 as the basis for updating subsequent drilling processes, ensuring the system maintains consistency in rules and can adjust based on actual feedback during drilling. By redefined the wall protection capacity state variables and their corresponding state interval constraints based on the changed mud concentration state parameters, and applying the redefined correspondences, state interval constraints, and mud concentration evolution paths to the determination and modification of mud concentration state parameters during subsequent drilling processes, the state determination, stability assessment, and control paths in subsequent drilling stages are continuously connected. This avoids mismatches caused by using previous correspondences or boundary settings in subsequent processes. The correspondence between mud concentration state parameters and wall protection capacity state parameters is redefined and applied to subsequent hole forming processes, including the following steps: Specifically, after completing a change in the mud concentration state parameter and causing the wall protection capacity state value to exit the unstable state range, the changes in the mud concentration state parameter before and after the change, as well as the corresponding changes in the wall protection capacity state value, are obtained. In one specific embodiment, after performing step four at a borehole depth of 20 meters, the mud concentration state parameter changes from 4.20 to 4.45, and the wall protection capacity state value increases from 1.05 to 1.15 and exits the unstable state range. Based on this, the change in the mud concentration state parameter before and after the change is obtained as 0.25, and the corresponding change in the wall protection capacity state value is obtained simultaneously as 0.10. This makes the changes in the mud concentration state parameter and the changes in the wall protection capacity state value form paired sample data under the same borehole depth and the same formation category parameter conditions, and the paired sample data is used as the input basis for subsequent updates of the corresponding relationship parameters.
[0063] Based on the changes in mud concentration state parameters and wall protection capacity state parameters, the change in wall protection capacity state parameters corresponding to a unit change in mud concentration state parameters is recalculated as the updated correspondence parameter. After obtaining the paired sample data, based on the ratio between the wall protection capacity state parameter change of 0.10 and the mud concentration state parameter change of 0.25, the change in wall protection capacity state parameters corresponding to a unit change in mud concentration state parameters is recalculated as 0.4, and 0.4 is determined as the updated correspondence parameter. In another embodiment, when two mud concentration state parameter changes are completed consecutively at the same drilling depth and two sets of paired sample data are obtained respectively, the change in wall protection capacity state parameters corresponding to two unit changes in mud concentration state parameters are calculated respectively, and the two calculation results are arithmetically averaged to determine the updated correspondence parameter, so that the updated correspondence parameter can reflect the latest trend of the correspondence at the current drilling depth.
[0064] The updated correspondence parameters are associated with the borehole depth location and formation type parameters, and the original correspondence parameters are replaced: After the updated correspondence parameter is determined to be 0.40, it is associated with the borehole depth location of 20 meters and the formation type parameter of silty clay. The original correspondence parameter that was previously associated with the borehole depth location and the formation type parameter is replaced with 0.40. This ensures that when calculating the wall protection capacity state quantity under the same borehole depth location and the same formation type parameter conditions, the updated correspondence parameter is used, and the correspondence parameter is iteratively updated with the latest control results of the borehole process.
[0065] In subsequent drilling processes, based on the updated correspondence parameters, the calculation of the wall protection capacity state quantity and the determination of the mud concentration evolution path are re-executed. This ensures that changes in the mud concentration state parameter during subsequent drilling stages are based on the updated correspondence parameters, achieving adaptive updates of the correspondence as the drilling process progresses. When the drilling process advances to a drilling depth of 21 meters and the formation type parameter remains silty clay, the calculation of the wall protection capacity state quantity is re-executed based on the updated correspondence parameter 0.40. After the wall protection capacity state quantity crosses the state boundary and enters the unstable state region, the determination of the mud concentration evolution path is re-executed based on the updated correspondence parameter 0.40 to convert the incremental target wall protection capacity state quantity into the total change in the target mud concentration state parameter. Subsequently, in step four, changes in the mud concentration state parameter during subsequent drilling stages are based on the updated correspondence parameters. After exiting the unstable state region for the next time, the change amount and recalculation process are repeated, thereby continuously replacing and updating the correspondence parameters along the drilling depth and the direction of advancement of the formation type parameter, forming a traceable adaptive update chain.
[0066] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters and thresholds in the formulas are set by those skilled in the art according to the actual situation.
[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A building pile foundation hole forming stability regulation method based on dynamic feedback of mud protection wall capacity, characterized in that, Comprise: Step one, determine the state determination rule of the mud concentration in the hole during the pile foundation hole forming process, establish the corresponding relationship between the mud concentration parameters corresponding to different hole forming depth positions and the corresponding hole forming stage, and form the state parameter set of the mud concentration in the hole during the hole forming process based on the corresponding relationship; Step two, based on the mud concentration state parameter set, determine the corresponding relationship between the mud concentration state parameter and the hole wall supporting effect, and map the mud concentration state parameter to the wall supporting capacity state quantity according to the corresponding relationship; Step three, according to the change of the wall supporting capacity state quantity in the hole forming process, determine the state interval constraint corresponding to the wall supporting capacity state quantity, and determine the state boundary defined by the state interval constraint; Step four, when the wall supporting capacity state quantity crosses the state boundary and enters the unstable state interval, according to the corresponding relationship between the mud concentration state parameter and the wall supporting capacity state quantity, determine the mud concentration evolution path matched with the change direction of the wall supporting capacity state quantity, and change the mud concentration state parameter according to the mud concentration evolution path; Step five, after the mud concentration state parameter changes, the wall supporting capacity state quantity and its corresponding state interval constraint are determined again based on the changed mud concentration state parameter, and the corresponding relationship, state interval constraint and mud concentration evolution path determined again are applied to the determination and change of the mud concentration state parameter in the subsequent hole forming process.
2. The building pile foundation hole-forming stability regulation method based on the dynamic feedback of the slurry wall protection capacity according to claim 1, characterized in that, In the step one, the determination of the mud concentration state determination rule comprises the following steps: Determine a plurality of sampling positions at a predetermined depth interval along the pile hole depth direction, and obtain mud concentration detection values at each sampling position at a predetermined time interval to form a continuous sampling sequence; The continuous sampling sequence is respectively subjected to time sequence smoothing and axial smoothing to generate a continuous state sequence corresponding to the hole forming process; Based on the continuous state sequence, the continuous change rate of the continuous state sequence with the hole forming process and its gradient along the hole forming axis are determined; Based on the continuous change rate and the gradient, the mud concentration state parameter set is formed, and the mud concentration state parameter set is associated with the corresponding hole forming depth position as the output of the state determination rule.
3. The building pile foundation hole-forming stability regulation method based on the dynamic feedback of the slurry wall protection capacity according to claim 1, characterized in that, The step of mapping the mud concentration state parameter to the wall supporting capacity state quantity based on the mud concentration state parameter set comprises the following steps: Obtain the mud density parameter and the mud viscosity parameter at the corresponding hole forming depth position, and associate the mud density parameter and the mud viscosity parameter with the mud concentration state parameter set according to the corresponding hole forming depth position; Based on the mud density parameter, calculate the unit volume mud weight, and combine the corresponding hole forming depth position to calculate the hole static pressure value; According to the mud rheological model, based on the mud viscosity parameter and the gradient parameter in the mud concentration state parameter set, the additional viscous supporting stress generated by the mud near the hole wall is calculated, and the hole static pressure value and the additional viscous supporting stress are linearly superimposed to obtain the equivalent supporting pressure value; Based on the formation density parameter at the corresponding hole forming depth position and the hole forming depth, the formation lateral pressure value is calculated, and the pressure ratio is calculated based on the equivalent supporting pressure value and the formation lateral pressure value, which is taken as the wall supporting capacity state quantity corresponding to the hole forming depth position.
4. The building pile foundation hole-forming stability regulation method based on the dynamic feedback of the slurry wall protection capacity according to claim 3, characterized in that, In the depth position matching relationship between the mud density parameter and the mud viscosity parameter and the mud concentration state parameter set is established: Based on the deviation degree between the corresponding depth position of the mud density parameter and the mud viscosity parameter and the corresponding hole forming depth position of the mud concentration state parameter set, the corresponding depth matching credibility parameter is determined; When calculating the equivalent supporting pressure value according to the mud density parameter and the mud viscosity parameter, the depth matching credibility parameter is used as a proportional coefficient to act on the hole static pressure value or the additional viscous supporting stress, so that the mud density parameter and the mud viscosity parameter corresponding to different depth matching credibility have different contribution degrees to the equivalent supporting pressure value.
5. The building pile foundation hole-forming stability regulation method based on the dynamic feedback of the slurry wall protection capacity according to claim 1, characterized in that, In step three, the determination of the state interval constraint corresponding to the wall protection capacity state quantity includes the following steps: According to the advancing order of the hole forming process, the wall protection capacity state quantity at the adjacent hole forming depth position is obtained, and the change value of the wall protection capacity state quantity is determined by calculating the difference between the adjacent wall protection capacity state quantities; Based on the change value, the sign consistency of the continuous N change values is judged to determine the change trend parameter of the wall protection capacity state quantity, wherein N is a predetermined number; Based on the formation category parameter and the hole forming condition parameter corresponding to the hole forming depth position, the engineering stability threshold and the engineering early warning threshold of the wall protection capacity state quantity are determined; When the wall protection capacity state quantity is less than the engineering early warning threshold and the change trend parameter indicates a continuous downward trend, it is determined that the wall protection capacity state quantity enters the unstable state interval; When the wall protection capacity state quantity is not less than the engineering early warning threshold and the change trend parameter indicates a continuous upward trend, it is determined that the wall protection capacity state quantity exits the unstable state interval; Based on the determination results of entering and exiting the unstable state interval, the state boundary defined by the state interval constraint is determined.
6. The building pile foundation hole-forming stability regulation method based on the dynamic feedback of the slurry wall protection capacity according to claim 1, characterized in that, In step four, the determination of the mud concentration evolution path includes the following steps: After the wall protection capacity state quantity crosses the state boundary and enters the unstable state interval, based on the corresponding relationship between the mud concentration state parameter and the wall protection capacity state quantity, the wall protection capacity state quantity change corresponding to the unit mud concentration state parameter change is determined; According to the deviation amplitude of the wall protection capacity state quantity relative to the state boundary, the target wall protection capacity state quantity increment required to restore the wall protection capacity state quantity to the state boundary is calculated; Based on the wall protection capacity state quantity change corresponding to the unit mud concentration state parameter change, the target wall protection capacity state quantity increment is converted into the target mud concentration state parameter change total amount; According to the target mud concentration state parameter change total amount, and combining the positive and negative directions of the target mud concentration state parameter change total amount, the mud concentration evolution path of the mud concentration state parameter changing from the current state to the target state is formed.
7. The building pile foundation hole-forming stability regulation method based on the dynamic feedback of the slurry wall protection capacity according to claim 6, characterized in that, In step four, changing the mud concentration state parameter according to the mud concentration evolution path includes the following steps: After the mud concentration evolution path is determined, the change process of the mud concentration state parameter is divided into multiple continuous adjustment stages; In each adjustment stage, the stage mud concentration state parameter change is determined according to the mud concentration evolution path, and the stage mud concentration state parameter change is limited to not more than the predetermined change upper limit; The upper limit of the predetermined change is determined according to the parameter of the sensitivity of the stratum corresponding to the current hole depth position to the change of the mud performance; After each adjustment stage is completed, the mud concentration state parameter is reacquired, and the wall protection capacity state quantity is recalculated based on the corresponding relationship between the mud concentration state parameter and the wall protection capacity state quantity; When the wall protection capacity state quantity is still in the unstable state interval, the next adjustment stage is continued to be executed, and when the wall protection capacity state quantity exits the unstable state interval, the change of the mud concentration state parameter is terminated.
8. The building pile foundation hole-forming stability regulation method based on the dynamic feedback of the slurry wall protection capacity according to claim 1, characterized in that: In step five, the corresponding relationship between the mud concentration state parameter and the wall protection capacity state quantity is re-determined and applied to the subsequent hole forming process, including the following steps: After the mud concentration state parameter is changed once and the wall protection capacity state quantity exits the unstable state interval, the change amount of the mud concentration state parameter before and after the change and the corresponding wall protection capacity state quantity change amount are acquired; Based on the mud concentration state parameter change amount and the wall protection capacity state quantity change amount, the wall protection capacity state quantity change amount corresponding to the unit mud concentration state parameter change amount is recalculated as the updated corresponding relationship parameter; The updated corresponding relationship parameter is associated with the hole depth position and the stratum category parameter, and replaces the original corresponding relationship parameter; In the subsequent hole forming process, the calculation of the wall protection capacity state quantity and the determination of the mud concentration evolution path are re-executed based on the updated corresponding relationship parameter; The change of the mud concentration state parameter in the subsequent hole forming stage is made according to the updated corresponding relationship parameter, so as to realize the adaptive update of the corresponding relationship with the hole forming process.