Intelligent detection system and method for building pile foundation

Abstract

The present application relates to the technical field of building pile foundation detection, and particularly relates to an intelligent detection system and method for building pile foundation, the system comprising a data acquisition module, a pile hole monitoring module, a pouring monitoring module and a pile body monitoring module; the method comprising: determining whether the pile hole meets the standard based on the disturbance range index; determining the initial guide pipe burial depth based on the hole wall stability index of the pile hole, and monitoring the rising speed of the concrete surface in the first pouring process to correct the initial guide pipe burial depth; determining whether the pouring speed of the concrete is qualified according to the comparison result of the thickness growth rate and the preset growth rate, so as to adjust the vibrating frequency of the guide pipe; completing the pile foundation concrete pouring under the condition that the pouring speed of the concrete is qualified, determining whether the pile foundation quality is at risk according to the pile body integrity index, and optimizing the preset growth rate according to the aggregate distribution index of the floating slurry layer. The present application improves the control precision of the pile foundation construction quality.

Description

Technical Field

[0001] This invention relates to the field of building pile foundation testing technology, and in particular to an intelligent testing system and method for building pile foundations. Background Technology

[0002] In building construction, pile foundations, as the core foundation components bearing the loads of the superstructure, directly determine the overall safety and durability of the building through their construction quality. Currently, the mainstream pile foundation testing methods in the industry mainly include low-strain reflected wave method, high-strain dynamic pile testing method, ultrasonic transmission method, and core drilling method. Although these methods are widely used in testing pile foundation integrity, bearing capacity, and concrete strength, they still have many technical bottlenecks in actual engineering scenarios and are difficult to adapt to the needs of modern building construction projects for refined, real-time, and intelligent management and control of pile foundation construction quality. Specifically, traditional testing methods are mostly post-construction, meaning testing can only be conducted after the pile foundation is completed. If defects such as broken piles, mud inclusions, or insufficient concrete strength are found, rework costs are extremely high and the construction period is severely delayed. The testing process is highly dependent on manual operation, and human error can easily lead to distorted test data. Moreover, the data processing cycle is long, and it is impossible to provide real-time feedback on construction quality issues. At the same time, existing testing equipment has relatively limited functions, focusing on single indicators, and it is difficult to collect key dynamic parameters during the pile foundation construction process simultaneously. This results in a disconnect between testing and construction, and it is impossible to form a closed-loop management system of testing-analysis-construction adjustment. In addition, traditional testing systems lack intelligent linkage capabilities with pile foundation construction equipment. During construction, it is impossible to dynamically optimize key parameters such as drilling speed and guide pipe burial depth based on real-time test data. Inappropriate construction parameters can easily lead to quality hazards such as borehole wall collapse and concrete segregation. As my country's construction projects develop towards super high-rise buildings, large spans, and complex geological conditions, the requirements for quality control of pile foundation construction are becoming increasingly stringent. The shortcomings of traditional testing methods in terms of real-time performance, accuracy, integration, and intelligence are becoming increasingly apparent. There is an urgent need to develop an intelligent testing system that can cover the entire pile foundation construction process, realize multi-parameter collaborative testing, intelligent data analysis, and construction linkage control, so as to improve the efficiency of pile foundation construction quality control and reduce project risks and costs.

[0003] Chinese Patent Application Publication No. CN117605103A discloses an intelligent testing method for photovoltaic pile foundations. The method utilizes a testing system constructed with scissor jacks, pressure sensors, distance sensors, inclinometers, controllers, support frames, cables, and mobile engineering machinery to perform compressive strength, tensile strength, and horizontal force testing on the pile foundations under test. This intelligent testing approach significantly improves testing efficiency, reduces manpower, shortens testing time, and enables rapid data collection. On the other hand, the accuracy of manual testing is easily affected by the individual factors of the testing personnel, leading to significant fluctuations in the accuracy and precision of the test data. Using an intelligent testing toolkit can reduce the interference of subjective factors, improve the consistency of test data, and reduce the error rate. This invention solves the problem of large-volume and low-efficiency pile foundation testing for photovoltaic power stations in desert areas.

[0004] The existing technology also has the following problems: When conducting pile foundation construction process inspection, the existing technology only relies on whether there is resistance or deformation during the lowering of the steel cage to judge whether there are problems such as diameter reduction or collapse of the pile hole. It cannot identify hidden hidden dangers in the hole wall in time during the lowering stage of the steel cage. Problems can only be found after the pile is completed by methods such as core drilling and ultrasonic testing, resulting in low accuracy of pile foundation construction quality control. Summary of the Invention

[0005] To address this, the present invention provides an intelligent detection system and method for building pile foundations, which overcomes the problem in the prior art that it is impossible to identify hidden hidden dangers in the borehole wall in a timely manner during the lowering stage of the reinforcing cage, and that problems can only be detected after the pile is formed by methods such as core drilling and ultrasonic testing, resulting in low accuracy in the control of pile foundation construction quality.

[0006] To achieve the above objectives, in one aspect, the present invention provides an intelligent detection method for building pile foundations, comprising: The pile holes are formed by rotary drilling, and the steel cage is lowered after the pile holes are cleaned a second time. Several surface images of the wall-protecting mud are acquired in real time during the lowering of the reinforcing cage. The disturbance characteristics of the mud are analyzed based on the surface images to calculate the disturbance range index, and the pile hole is determined to meet the standard based on the disturbance range index. Under the condition that the pile hole meets the standard, the guide pipe is placed and concrete is poured. The initial burial depth of the guide pipe is determined based on the hole wall stability index, and the rising speed of the concrete surface during the first pouring process is monitored to correct the initial burial depth of the guide pipe. The thickness growth rate of the laitance layer during the continuous concrete pouring stage is obtained, and the pouring speed of the concrete is determined to be qualified based on the comparison result of the thickness growth rate and the preset growth rate, so as to adjust the vibration frequency of the duct. Under the condition that the concrete pouring speed is qualified, the pile foundation concrete pouring is completed. After the concrete has cured, the pile integrity index is determined to determine whether there is a risk to the pile foundation quality. The preset growth rate is optimized according to the aggregate distribution index of the laitance layer.

[0007] Furthermore, the process of determining the disturbance range index includes: After processing a single surface image, the surface image is divided into several annular regions at equal intervals, with the geometric center of the pile hole as the reference point, and the texture entropy of the annular regions is determined. Based on the comparison result that the texture entropy is greater than or equal to the preset entropy, the annular region is determined to be the liquid surface disturbance region, and the liquid surface disturbance range of a single surface image is determined. The coefficient of variation of several liquid surface disturbance ranges is determined as the disturbance range index.

[0008] Furthermore, the process of determining whether the pile hole meets the standard based on the disturbance range index includes: Compare the disturbance range index with a preset index; The pile hole meets the standard based on the comparison result that the disturbance range index is less than or equal to the preset index.

[0009] Furthermore, under the condition that the pile hole meets the standards, the process of determining the initial tremie pipe embedment depth based on the hole wall stability index, and correcting the initial tremie pipe embedment depth based on the rising rate of the concrete surface includes: The difference between the sum of the products of the soil internal friction angle, soil cohesion, and static pressure of the wall-protecting mud with their corresponding weighting coefficients, and the sum of the products of the pile hole diameter and pore water pressure with their corresponding weighting coefficients, is determined as the hole wall stability index. The initial burial depth of the conduit is determined based on the pore wall stability index; The ascent speed is compared with the preset speed; The initial catheter burial depth is reduced based on the comparison result that the rising speed is less than the first preset speed; The initial catheter burial depth is increased based on the comparison result that the rising speed is greater than the second preset speed; Wherein, the first preset speed is less than the second preset speed.

[0010] Furthermore, the process of determining whether the concrete pouring rate is qualified based on the thickness growth rate of the laitance layer during the continuous pouring stage includes: The thickness growth rate is compared with the preset growth rate. The concrete pouring speed is determined to be unqualified based on the comparison result that the thickness growth rate is greater than the first preset growth rate or less than the second preset growth rate. Wherein, the first preset growth rate is greater than the second preset growth rate.

[0011] Furthermore, when the concrete pouring speed is determined to be substandard, the process of adjusting the vibration frequency of the tremie pipe includes: The difference between the thickness growth rate and the preset growth rate is used to obtain a relative difference value; Based on the comparison result between the relative difference and the preset relative difference, several frequency adjustment coefficients are set to adjust the vibration frequency of the conduit.

[0012] Furthermore, the process of determining whether there is a risk to the quality of the pile foundation based on the pile integrity index includes: The pile integrity index is compared with a preset integrity index; Based on the comparison result that the pile integrity index is greater than the preset integrity index, it is determined that there is a risk in the quality of the pile foundation.

[0013] Furthermore, the process of determining the aggregate distribution index of the laitance layer includes: The laitance layer is divided into several layers at equal intervals, and the aggregate content of a single laitance layer is determined. The aggregate distribution index of the laitance layer is determined based on the ratio of the difference in aggregate content between two adjacent single-layer laitance layers.

[0014] Furthermore, under the condition that the quality of the pile foundation is at risk, the process of optimizing the preset growth rate based on the aggregate distribution index includes: The aggregate distribution index is compared with a preset distribution index; Based on the comparison result that the aggregate distribution index is greater than the preset distribution index, the preset growth rate is optimized by the preset index adjustment coefficient.

[0015] On the other hand, the present invention also provides an intelligent detection system for building pile foundations, comprising: The data acquisition module includes an image acquisition device for acquiring surface images of the wall-protecting mud, an accelerometer for acquiring mechanical vibration signals at the top of the pile, and an ultrasonic level gauge for determining the liquid level position. The pile hole monitoring module is used to determine the disturbance range index based on the surface image to determine whether the pile hole meets the standard, to determine the initial duct burial depth based on the pile hole wall stability index, and to determine the rising speed of the concrete surface during the first pouring process based on the ultrasonic level gauge to correct the initial duct burial depth. The grouting monitoring module is used to determine the thickness growth rate of the slurry layer during the continuous grouting stage based on the ultrasonic level gauge, to determine whether the concrete grouting speed is qualified based on the comparison result of the thickness growth rate and the preset growth rate, and to adjust the vibration frequency of the duct based on the unqualified condition. The pile body monitoring module is used to determine the pile body integrity index based on the monitoring results of the acceleration sensor, under the condition that the concrete pouring process is qualified, so as to determine whether there is a risk to the quality of the pile foundation, and optimize the preset growth rate based on the aggregate distribution index of the laitance layer.

[0016] Compared with existing technologies, the advantages of this invention lie in its ability to dynamically determine the pile hole's compliance status during the rebar cage lowering stage by real-time acquisition of images of the protective mud surface and calculation of the disturbance range index. This is achieved by comparing the disturbance range index with a preset threshold and quantifying the process using the coefficient of variation of the annular region's texture entropy. The disturbance characteristics of the pile hole's protective mud directly reflect the hole wall stability and the impact of the rebar cage lowering on the surrounding soil. Relying solely on experience or fixed-time hole cleaning makes it difficult to identify hidden problems such as localized hole collapse or excessive mud cake. The disturbance range index comprehensively reflects the spatial uniformity of the liquid surface disturbance and the intensity of its temporal fluctuations; its deviation from the preset value accurately characterizes potential hole wall risks. Timely warnings and interventions when lowering fails to meet standards avoid hole wall instability or pile quality defects caused by blind cage lowering in traditional processes, thereby improving the accuracy of pile foundation construction quality control.

[0017] Furthermore, this invention uses an ultrasonic level gauge to monitor the growth rate of the laitance layer thickness in real time during the concrete pouring stage. Combined with the initial concrete surface rise rate and borehole wall stability index, it provides a multi-parameter collaborative assessment of the pouring process stability, overcoming the limitations of traditional methods that rely solely on pouring volume estimation. The adjustment of the guide pipe embedment depth and vibration frequency directly affects the concrete density and laitance layer development. The thickness growth rate can detect abnormalities in concrete fluidity or segregation trends in advance, rather than discovering defects only after the pile body has solidified through integrity testing. When the pouring speed is unqualified, a graded adjustment strategy for the vibration frequency is adopted based on the synergistic judgment of the relative difference in the thickness growth rate and the thickness of the interface transition layer, rather than the traditional empirical adjustment. The relative difference threshold judgment can accurately distinguish between slight fluctuations and severe anomalies, specifically restoring the uniformity and density of the concrete. This avoids improper parameter adjustment exacerbating laitance layer thickening or uneven aggregate distribution, thereby improving the accuracy of pile foundation construction quality control.

[0018] Furthermore, this invention assesses pile quality after pile solidification by detecting the pile integrity index and the aggregate distribution index of the laitance layer. Based on the aggregate distribution index, it optimizes the preset growth rate threshold during the grouting stage, constructing a closed-loop control system for construction process monitoring, pile quality assessment, and process parameter optimization. The aggregate distribution index directly reflects the uniformity and segregation of concrete grouting. An abnormality indicates improper grouting speed control leading to laitance layer component imbalance. The difference between the distribution index and the preset value can pinpoint the deviation from the speed control standard. When the difference exceeds the preset value, the growth rate threshold is significantly optimized by adjusting the coefficient to improve grouting control requirements. Simultaneously, the decentralization of disturbance monitoring, grouting stability control, and final pile evaluation forms a three-level quality control system. This ensures precise control of parameters at each process stage and continuously iterates construction standards through a feedback mechanism, significantly improving the overall uniformity and bearing reliability of the pile foundation, thereby enhancing the accuracy of pile foundation construction quality control. Attached Figure Description

[0019] Figure 1 This is a flowchart of an intelligent detection method for building pile foundations according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating how to determine whether a pile hole meets the standards according to an embodiment of the present invention; Figure 3 A flowchart for determining whether the concrete pouring speed is qualified according to an embodiment of the present invention; Figure 4 This is a structural block diagram of an intelligent detection system for building pile foundations according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the pile foundation according to an embodiment of the present invention; In the diagram: 1. Reinforcing cage; 2. Pile foundation. Detailed Implementation

[0020] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0021] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0022] Please see Figure 1 As shown, it is a flowchart of an intelligent detection method for building pile foundations according to an embodiment of the present invention.

[0023] The present invention provides an intelligent detection method for building pile foundations, comprising: Step S1: A pile hole is formed by rotary drilling, and the pile hole is cleaned twice before the steel cage is lowered. Step S2: During the lowering of the reinforcing cage, acquire several surface images of the wall-protecting mud in real time, analyze the disturbance characteristics of the mud based on the surface images and calculate the disturbance range index, and determine whether the pile hole meets the standard based on the disturbance range index. Step S3: Under the condition that the pile hole meets the standard, the guide pipe is placed and concrete is poured. The initial burial depth of the guide pipe is determined based on the hole wall stability index, and the rising speed of the concrete surface during the first pouring process is monitored to correct the initial burial depth of the guide pipe. Step S4: Obtain the thickness growth rate of the laitance layer during the continuous concrete pouring stage, and determine whether the concrete pouring speed is qualified based on the comparison result of the thickness growth rate and the preset growth rate, so as to adjust the vibration frequency of the duct. Step S5: Under the condition that the concrete pouring speed is qualified, the pile foundation concrete pouring is completed. After the concrete has solidified, the pile integrity index is determined to determine whether there is a risk to the pile foundation quality. The preset growth rate is optimized according to the aggregate distribution index of the laitance layer.

[0024] Specifically, in this embodiment of the invention, the main reinforcement and stiffening reinforcement of the steel cage are all welded. The steel bar joints should be staggered by a distance of not less than 35d and 500mm, respectively. The number of steel bar joints in the same cross-section of the same steel cage should not exceed 50%. Steel bar joints should avoid the pile bottom area. Within a 4m range from the pile top, the spacing between the same steel bar joint should be greater than 3m. Starting from the first stiffening ring at the top of the steel cage, a protective layer is set every 4 meters, with 3 to 4 layers per group. The protective layer thickness is 50mm, and protective reinforcement or concrete spacers are used for the protective layer.

[0025] In this embodiment of the invention, the maximum water-cement ratio of the concrete is 0.5, the maximum chloride ion content is less than or equal to 0.15% (the percentage of chloride ion mass to cementitious material mass), and the maximum alkali content is less than or equal to 3 kg / m³. 3 The slump range is 180mm to 220mm; the depth of the pile top embedded in the pile cap is 50mm; a pre-design test pile should be carried out before the pile foundation construction; the characteristic value of the single pile bearing capacity should be determined by the single pile static load test of the pre-design test pile; the standard value of the ultimate bearing capacity is 18000KN.

[0026] Specifically, the process of determining the disturbance range index includes: After processing a single surface image, the surface image is divided into several annular regions at equal intervals, with the geometric center of the pile hole as the reference point, and the texture entropy of the annular regions is determined. Based on the comparison result that the texture entropy is greater than or equal to the preset entropy, the annular region is determined to be the liquid surface disturbance region, and the liquid surface disturbance range of a single surface image is determined. The coefficient of variation of several liquid surface disturbance ranges is determined as the disturbance range index.

[0027] Please see Figure 2 As shown, it is a flowchart for determining whether a pile hole meets the standards according to an embodiment of the present invention.

[0028] Specifically, the process of determining whether a pile hole meets the standard based on the disturbance range index includes: Compare the disturbance range index with a preset index; The pile hole meets the standard based on the comparison result that the disturbance range index is less than or equal to the preset index; The pile hole is determined to be substandard based on the comparison result that the disturbance range index is greater than the preset index.

[0029] Specifically, the processing of a single surface image includes, but is not limited to, grayscale conversion, filtering, and noise reduction. The surface image is divided into several annular regions at equal intervals, and the interval can be set to 1cm, 3cm, or 5cm, without any specific limitation. The texture entropy of the annular regions is determined based on image algorithms, which is existing technology and will not be described in detail here.

[0030] Specifically, the preset entropy is set to a range of [2nat, 5nat], and preferably 4nat in this embodiment of the invention; the preset exponent is set to a range of [0.2, 0.4], and preferably 0.3 in this embodiment of the invention. However, the above values ​​are only examples, and those skilled in the art can choose values ​​according to actual needs.

[0031] Understandably, the essence of the disturbance range index is to quantify the spatial range and temporal stability of the surface disturbance of the drilling mud. The disturbance state of the mud is directly determined by the stability of the pile hole. When there are no defects such as borehole shrinkage, local collapse, or spalling, the mud is only subject to slight and controllable disturbance from the uniform descent of the reinforcing cage. When the reinforcing cage is lowered, it only pushes the mud close to the cage wall (3cm to 5cm) upward. The mud surface is generally calm, the texture entropy of the annular region is low, and the disturbance range of a single image accounts for only 10% to 15% of the liquid surface area. If there are defects such as slight shrinkage or local spalling in the borehole wall, the shrinkage will compress the space inside the hole, forcing the mud to flow into the non-shrinkage area, resulting in an expansion of the local mud disturbance range. The texture entropy of the corresponding annular region is greater than the preset entropy. Spalling from the borehole wall will fall into the mud, forming a local vortex, causing the texture entropy of the annular region corresponding to the spalling location to rise sharply. The disturbance range breaks through the normal boundary, resulting in a larger disturbance range index. Traditional methods require waiting until the lowering of the reinforcing cage is obstructed, such as when the diameter narrows and compresses the cage, causing a sudden increase in resistance, before discovering problems with the borehole wall. By this time, the borehole wall defects have already developed to a significant stage. However, the disturbance range index can capture signals in the early stages of defects. For example, when there is a slight diameter narrowing in the borehole wall, it will only cause local disturbance of the mud. The disturbance range index will rise before the reinforcing cage is obstructed. The borehole wall can be judged to be substandard by the index exceeding the standard, and work can be stopped in advance.

[0032] Specifically, under the condition that the pile hole meets the standards, the process of determining the initial tremie pipe embedment depth based on the hole wall stability index, and correcting the initial tremie pipe embedment depth based on the rising rate of the concrete surface includes: The difference between the sum of the products of the soil internal friction angle, soil cohesion, and static pressure of the wall-protecting mud with their corresponding weighting coefficients, and the sum of the products of the pile hole diameter and pore water pressure with their corresponding weighting coefficients, is determined as the hole wall stability index. The initial burial depth of the conduit is determined based on the pore wall stability index; The ascent speed is compared with the preset speed; Based on the comparison result that the upward speed is less than the first preset speed, the initial catheter burial depth is reduced; Based on the comparison result that the upward speed is greater than the second preset speed, the initial catheter burial depth is increased; Wherein, the first preset speed is less than the second preset speed.

[0033] Specifically, the first preset speed is set to 1 m / h, and the second preset speed is set to 1.5 m / h. However, the above values ​​are only examples, and those skilled in the art can choose values ​​according to actual needs.

[0034] Specifically, the internal friction angle of the soil, soil cohesion, and static pressure of the retaining mud are parameters that positively influence borehole stability. The internal friction angle and soil cohesion are determined based on geological survey results, and the static pressure of the retaining mud is the product of mud specific gravity, gravitational acceleration, and depth of the measurement point, with corresponding weighting coefficients of 0.4, 0.35, and 0.25, respectively. The pile hole diameter and pore water pressure are parameters that negatively influence borehole stability. The pile hole diameter is determined according to design requirements, and the pore water pressure is the measurement result of a water pressure gauge, with corresponding weighting coefficients of 0.6 and 0.4, respectively. The above values ​​are not limited to these, and those skilled in the art can choose values ​​according to actual conditions.

[0035] Specifically, a pre-set relationship between the borehole wall stability index and the duct burial depth is established. In this embodiment, the duct burial depth ranges from 2m to 6m. The initial duct burial depth is based on the theoretical value of the borehole wall stability index. If the stability index is high, the initial duct burial depth is 3m to 4m; if the stability index is low, the initial duct burial depth is 2m to 3m. The initial duct burial depth only considers borehole wall stability and does not consider actual factors such as concrete fluidity and duct inner wall resistance. If the concrete slump is insufficient, the flow resistance increases. Even if the initial burial depth is compliant, the concrete rising speed will be less than the preset speed. In this case, the concrete cannot sink or disperse in the duct, which can easily lead to blockage. Reducing the burial depth during correction can reduce the concrete flow resistance. The smaller the burial depth, the less pressure the concrete around the duct needs to overcome during concrete diffusion, thus increasing the rising speed to the compliant range. If the inner wall of the duct is smooth and the concrete has good fluidity, the initial burial depth may cause the concrete rising speed to be greater than the preset speed. In this case, the concrete diffuses too quickly, which can easily lead to a sudden drop in local burial depth and cause mud backflow. Increasing the burial depth during correction can slow down the diffusion speed by increasing the amount of concrete around the duct, thus maintaining a stable rising speed.

[0036] Specifically, under the condition of reducing the initial catheter burial depth, the first preset speed is subtracted from the rising speed to obtain a first speed difference value; Based on the comparison result that the first speed difference is greater than the preset speed difference, the initial catheter burial depth is determined to be reduced by the first depth adjustment coefficient; Based on the comparison result that the first speed difference is less than or equal to the preset speed difference, the initial catheter burial depth is reduced by a second depth adjustment coefficient.

[0037] Specifically, under the condition of increasing the initial catheter burial depth, the difference between the rising speed and the second preset speed is used to obtain the second speed difference value; Based on the comparison result that the second speed difference is greater than the preset speed difference, the initial catheter burial depth is increased by a third depth adjustment coefficient; Based on the comparison result that the second speed difference is less than or equal to the preset speed difference, the initial catheter burial depth is increased by a fourth depth adjustment coefficient.

[0038] Specifically, the preset speed difference value is set to a range of [0.2 m / h, 0.4 m / h], preferably 0.3 m / h in this embodiment; the first depth adjustment coefficient is set to a range of [0.85, 0.92], preferably 0.88 in this embodiment; the second depth adjustment coefficient is set to a range of [0.93, 0.95], preferably 0.94 in this embodiment; the third depth adjustment coefficient is set to a range of [1.08, 1.15], preferably 1.1 in this embodiment; and the fourth depth adjustment coefficient is set to a range of [1.03, 1.07], preferably 1.05 in this embodiment. However, the above values ​​are only examples, and those skilled in the art can choose values ​​according to actual needs.

[0039] Please see Figure 3 As shown, it is a flowchart for determining whether the concrete pouring speed is qualified according to an embodiment of the present invention.

[0040] Specifically, the process of determining whether the concrete pouring rate is qualified based on the thickness growth rate of the laitance layer during the continuous pouring stage includes: The thickness growth rate is compared with the preset growth rate. The concrete pouring speed is determined to be unqualified based on the comparison result that the thickness growth rate is greater than the first preset growth rate or less than the second preset growth rate. The concrete pouring speed is determined to be qualified based on the comparison result that the thickness growth rate is less than or equal to the first preset growth rate and greater than or equal to the second preset growth rate; Wherein, the first preset growth rate is greater than the second preset growth rate.

[0041] Specifically, the first preset growth rate is 0.8 cm / h, and the second preset growth rate is 2 cm / h.

[0042] Understandably, when the pouring speed is too fast, the new concrete rushes into the pile hole, which will squeeze and disturb the existing concrete in the pile hole. The impact force of the new concrete will destroy the already formed laitance layer, and some laitance will be trapped inside the concrete, resulting in a slow increase in the thickness of the laitance layer. If the laitance is too thin, it may not be able to completely isolate the mud, and the mud will easily mix into the concrete during subsequent pouring, forming mud inclusion defects. When the pouring speed is too slow, the concrete bleeds fully, a large amount of free water floats to the surface, the cement paste generated increases, the aggregate settles fully, and a large amount of fine aggregate floats to the surface with the cement paste, resulting in a rapid accumulation of laitance layer thickness. If the laitance is too thick, it will encroach on the effective pile height, and the pile length may be insufficient after the laitance is removed later.

[0043] Specifically, when the concrete pouring speed is determined to be substandard, the process of adjusting the vibration frequency of the tremie pipe includes: The difference between the thickness growth rate and the preset growth rate is used to obtain a relative difference value; Based on the comparison result between the relative difference and the preset relative difference, several frequency adjustment coefficients are set to adjust the vibration frequency of the conduit.

[0044] Specifically, when the thickness growth rate is greater than the first preset growth rate, the difference between the thickness growth rate and the first preset growth rate is used to obtain a first relative difference; Based on the comparison result that the first relative difference is greater than the preset relative difference, the vibration frequency of the guide tube is reduced by the first frequency adjustment coefficient. Based on the comparison result that the first relative difference is less than or equal to the preset relative difference, the vibration frequency of the conduit is reduced by a second frequency adjustment coefficient.

[0045] Specifically, when the thickness growth rate is less than the second preset growth rate, the difference between the second preset growth rate and the thickness growth rate is used to obtain a second relative difference; Based on the comparison result that the second relative difference is greater than the preset relative difference, the vibration frequency of the conduit is increased by a third frequency adjustment coefficient. Based on the comparison results where the second relative difference is smaller than or equal to the preset relative difference, the vibration frequency of the conduit is increased by a fourth frequency adjustment coefficient.

[0046] Specifically, the preset relative difference range is set to [10%, 20%], preferably 15% in this embodiment; the first frequency adjustment coefficient range is set to [0.6, 0.7], preferably 0.65 in this embodiment; the second frequency adjustment coefficient range is set to [0.8, 0.9], preferably 0.84 in this embodiment; the third frequency adjustment coefficient range is set to [1.2, 1.3], preferably 1.25 in this embodiment; and the fourth frequency adjustment coefficient range is set to [1.1, 1.19], preferably 1.15 in this embodiment. However, the above values ​​are only examples, and those skilled in the art can also choose values ​​according to actual needs.

[0047] Specifically, the process of determining whether there is a risk to the quality of pile foundations based on the pile integrity index includes: The pile integrity index is compared with a preset integrity index; Based on the comparison result that the pile integrity index is greater than the preset integrity index, it is determined that there is a risk in the quality of the pile foundation; Based on the comparison results of the pile integrity index being less than or equal to the preset integrity index, it is determined that there is no risk to the quality of the pile foundation.

[0048] Specifically, the pile integrity index is determined using the low-strain reflected wave method. An accelerometer is installed at the top of the pile, and a hammer is used to lightly strike the center of the pile top. When the hammer strikes the pile top, it generates a low-frequency stress wave that propagates downwards along the pile. When the stress wave encounters a pile defect, such as mud inclusion, diameter reduction, or the pile bottom, it is reflected back to the pile top, causing a slight vibration at the pile top. The stress wave propagation signal is collected, and the ratio of the absolute value of the maximum amplitude of the defect reflected wave to the absolute value of the maximum amplitude of the pile bottom reflected wave is determined as the pile integrity index. The smaller the ratio, the better the pile integrity. This is existing technology and will not be elaborated further.

[0049] Specifically, the preset integrity index is set to 0.1.

[0050] Specifically, the process of determining the aggregate distribution index of the laitance layer includes: Based on the interface between the laitance layer and the dense concrete, the laitance layer is divided into several layers at equal intervals from top to bottom, with each layer having a thickness of 1 / 5 of the total thickness of the laitance layer. The aggregate content in each layer was tested one by one using the volume percentage method. The aggregate content of the topmost layer of the laitance layer was the first test result, and the aggregate content of the bottommost layer of the laitance layer was the last test result. The positive difference ratio of aggregate content in each adjacent layer is determined sequentially, and results with a positive difference ratio less than 0 are discarded. The coefficient of variation of the remaining positive difference ratio is determined as the aggregate distribution index of the laitance layer; The positive difference ratio is determined as follows: the ratio of the difference between the aggregate content of the subsequent layer and the aggregate content of the previous layer to the aggregate content of the previous layer.

[0051] Specifically, given that there is a risk to the quality of the pile foundation, the process of optimizing the preset growth rate based on the aggregate distribution index includes: The aggregate distribution index is compared with a preset distribution index; Based on the comparison result that the aggregate distribution index is greater than the preset distribution index, it is determined that the first preset growth rate is increased by the first preset index adjustment coefficient, and the second preset growth rate is decreased by the second preset index adjustment coefficient.

[0052] Specifically, the preset distribution index ranges from [0.3, 0.5], with 0.4 being preferred in this embodiment; the first preset index adjustment coefficient ranges from [1.17, 1.25], with 1.23 being preferred in this embodiment; and the second preset index adjustment coefficient ranges from [0.92, 0.97], with 0.95 being preferred in this embodiment. However, the above values ​​are merely examples, and those skilled in the art can choose values ​​according to actual needs.

[0053] Please see Figure 4 andFigure 5 As shown, Figure 4 This is a structural block diagram of an intelligent detection system for building pile foundations according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the pile foundation according to an embodiment of the present invention.

[0054] The present invention provides an intelligent detection system for building pile foundations, comprising: The data acquisition module includes an image acquisition device for acquiring surface images of the wall-protecting mud, an accelerometer for acquiring mechanical vibration signals at the top of the pile, and an ultrasonic level gauge for determining the liquid level position. The pile hole monitoring module is used to determine the disturbance range index based on the surface image to determine whether the pile hole meets the standard, to determine the initial duct burial depth based on the pile hole wall stability index, and to determine the rising speed of the concrete surface during the first pouring process based on the ultrasonic level gauge to correct the initial duct burial depth. The grouting monitoring module is used to determine the thickness growth rate of the slurry layer during the continuous grouting stage based on the ultrasonic level gauge, to determine whether the concrete grouting speed is qualified based on the comparison result of the thickness growth rate and the preset growth rate, and to adjust the vibration frequency of the duct based on the unqualified condition. The pile body monitoring module is used to determine the pile body integrity index based on the monitoring results of the acceleration sensor, under the condition that the concrete pouring process is qualified, so as to determine whether there is a risk to the quality of the pile foundation, and optimize the preset growth rate based on the aggregate distribution index of the laitance layer.

[0055] Specifically, the image acquisition device model is such as the Hikvision DS-2XC3046-L camera, and there is no specific limitation; the accelerometer model is such as the Langstec ULT2004A piezoelectric accelerometer, and there is no specific limitation; the ultrasonic level gauge model is such as the Siemens SITRANS LUT430, and there is no specific limitation.

[0056] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. An intelligent detection method for building pile foundations, characterized in that, include: The pile holes are formed by rotary drilling, and the steel cage is lowered after the pile holes are cleaned a second time. Several surface images of the wall-protecting mud are acquired in real time during the lowering of the reinforcing cage. The disturbance characteristics of the mud are analyzed based on the surface images to calculate the disturbance range index, and the pile hole is determined to meet the standard based on the disturbance range index. Under the condition that the pile hole meets the standard, the guide pipe is placed and concrete is poured. The initial burial depth of the guide pipe is determined based on the hole wall stability index, and the rising speed of the concrete surface during the first pouring process is monitored to correct the initial burial depth of the guide pipe. The thickness growth rate of the laitance layer during the continuous concrete pouring stage is obtained, and the pouring speed of the concrete is determined to be qualified based on the comparison result of the thickness growth rate and the preset growth rate, so as to adjust the vibration frequency of the duct. Under the condition that the concrete pouring speed is qualified, the pile foundation concrete pouring is completed. After the concrete has cured, the pile integrity index is determined to determine whether there is a risk to the pile foundation quality. The preset growth rate is optimized according to the aggregate distribution index of the laitance layer.

2. The intelligent detection method for building pile foundations according to claim 1, characterized in that, The process of determining the disturbance range index includes: After processing a single surface image, the surface image is divided into several annular regions at equal intervals, with the geometric center of the pile hole as the reference point, and the texture entropy of the annular regions is determined. Based on the comparison result that the texture entropy is greater than or equal to the preset entropy, the annular region is determined to be the liquid surface disturbance region, and the liquid surface disturbance range of a single surface image is determined. The coefficient of variation of several liquid surface disturbance ranges is determined as the disturbance range index.

3. The intelligent detection method for building pile foundations according to claim 2, characterized in that, The process of determining whether a pile hole meets the standard based on the disturbance range index includes: Compare the disturbance range index with a preset index; The pile hole meets the standard based on the comparison result that the disturbance range index is less than or equal to the preset index.

4. The intelligent detection method for building pile foundations according to claim 3, characterized in that, Under the condition that the pile hole meets the standards, the process of determining the initial tremie pipe embedment depth based on the hole wall stability index, and correcting the initial tremie pipe embedment depth based on the concrete surface rise rate includes: The difference between the sum of the products of the soil internal friction angle, soil cohesion, and static pressure of the wall-protecting mud with their corresponding weighting coefficients, and the sum of the products of the pile hole diameter and pore water pressure with their corresponding weighting coefficients, is determined as the hole wall stability index. The initial burial depth of the conduit is determined based on the pore wall stability index; The ascent speed is compared with the preset speed; The initial catheter burial depth is reduced based on the comparison result that the rising speed is less than the first preset speed; The initial catheter burial depth is increased based on the comparison result that the rising speed is greater than the second preset speed; Wherein, the first preset speed is less than the second preset speed.

5. The intelligent detection method for building pile foundations according to claim 4, characterized in that, The process of determining whether the concrete pouring rate is qualified based on the thickness growth rate of the laitance layer during the continuous pouring stage includes: The thickness growth rate is compared with the preset growth rate. The concrete pouring speed is determined to be unqualified based on the comparison result that the thickness growth rate is greater than the first preset growth rate or less than the second preset growth rate. Wherein, the first preset growth rate is greater than the second preset growth rate.

6. The intelligent detection method for building pile foundations according to claim 5, characterized in that, When the concrete pouring speed is determined to be substandard, the process of adjusting the vibration frequency of the tremie pipe includes: The difference between the thickness growth rate and the preset growth rate is used to obtain a relative difference value; Based on the comparison result between the relative difference and the preset relative difference, several frequency adjustment coefficients are set to adjust the vibration frequency of the conduit.

7. The intelligent detection method for building pile foundations according to claim 6, characterized in that, The process of determining whether there is a risk to the quality of pile foundations based on the pile integrity index includes: The pile integrity index is compared with a preset integrity index; Based on the comparison result that the pile integrity index is greater than the preset integrity index, it is determined that there is a risk in the quality of the pile foundation.

8. The intelligent detection method for building pile foundations according to claim 7, characterized in that, The process of determining the aggregate distribution index of the laitance layer includes: The laitance layer is divided into several layers at equal intervals, and the aggregate content of a single laitance layer is determined. The aggregate distribution index of the laitance layer is determined based on the ratio of the difference in aggregate content between two adjacent single-layer laitance layers.

9. The intelligent detection method for building pile foundations according to claim 8, characterized in that, Under the condition that there is a risk to the quality of the pile foundation, the process of optimizing the preset growth rate based on the aggregate distribution index includes: The aggregate distribution index is compared with a preset distribution index; Based on the comparison result that the aggregate distribution index is greater than the preset distribution index, the preset growth rate is optimized by the preset index adjustment coefficient.

10. A detection system applying the intelligent detection method for building pile foundations according to any one of claims 1-9, characterized in that, include: The data acquisition module includes an image acquisition device for acquiring surface images of the wall-protecting mud, an accelerometer for acquiring mechanical vibration signals at the top of the pile, and an ultrasonic level gauge for determining the liquid level position. The pile hole monitoring module is used to determine the disturbance range index based on the surface image to determine whether the pile hole meets the standard, to determine the initial duct burial depth based on the pile hole wall stability index, and to determine the rising speed of the concrete surface during the first pouring process based on the ultrasonic level gauge to correct the initial duct burial depth. The grouting monitoring module is used to determine the thickness growth rate of the slurry layer during the continuous grouting stage based on the ultrasonic level gauge, to determine whether the concrete grouting speed is qualified based on the comparison result of the thickness growth rate and the preset growth rate, and to adjust the vibration frequency of the duct based on the unqualified condition. The pile body monitoring module is used to determine the pile body integrity index based on the monitoring results of the acceleration sensor, under the condition that the concrete pouring process is qualified, so as to determine whether there is a risk to the quality of the pile foundation, and optimize the preset growth rate based on the aggregate distribution index of the laitance layer.

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