Pile forming form and inter-pile soil compactness evaluation method based on vibro-replacement gravel pile construction data

Abstract

The invention discloses a pile forming form and inter-pile soil compactness evaluation method based on vibro-replacement gravel pile construction data. The method comprises the steps of finding a pseudo-residual vibration working section according to a real-time construction depth-time curve, determining a key stage according to a real-time construction filling amount-time curve, finally finding a time node of downward insertion / upward pulling of a gravel pile by a vibroflot according to an amplitude change rule of a real-time construction current-time curve, calculating a transverse extrusion and expansion range after reinforcement, and finally determining a reinforcement result. And the pile forming form is estimated, and the average compactness of the soil between the piles of the reinforced field is calculated. According to the method, evaluation of the pile forming form and the compactness of the soil between the piles is achieved through on-site construction data, and the method has the advantages of being high in evaluation speed, high in accuracy and the like and is suitable for reinforcing effect evaluation of the vibro-replacement gravel pile treatment foundation with the down-inserting and up-pulling construction technology.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of foundation treatment technology construction quality evaluation, and particularly relates to a pile forming mode and soil density between piles evaluation method based on construction data of vibroflotation gravel pile. BACKGROUND

[0002] In recent years, soft foundation treatment plays an increasingly important role in national major strategic projects. Vibroflotation gravel pile composite foundation can improve the bearing capacity of soft foundation, form a natural vertical drainage path to speed up the drainage and consolidation of soil, and has the characteristics of simple construction process, low cost, easy access to pile materials, etc.

[0003] During the construction of vibroflotation method, the construction quality needs to be controlled to make the reinforcement effect meet the design requirements. Pile diameter is a key indicator for the design and construction control of vibroflotation gravel pile, and is an important content of construction quality inspection. The existing pile diameter calculation method mostly calculates the change of pile diameter along the depth according to the information such as gravel filling amount and vibration depth collected during the vibroflotation construction process to analyze the pile forming mode of gravel pile, but it is difficult to reflect the volume change of gravel filling after being inserted, extruded, left and vibrated by the vibrator. The compaction coefficient recommended by the existing specification is not targeted for some vibroflotation engineering cases. SUMMARY

[0004] In order to solve the problems in the background art, the application provides a method for calculating the pile forming mode based on the construction information of vibroflotation to evaluate the soil density between piles.

[0005] The technical scheme of the application is as follows: The pile forming mode and soil density between piles evaluation method based on the construction data of vibroflotation gravel pile comprises the following steps: Step S1, extracting real-time depth, real-time current and real-time construction filling amount data of the vibroflotation gravel pile construction process in the vibroflotation and automatic filling machine; specifically, extracting real-time depth and real-time current data from the built-in system of the vibrator, and extracting real-time construction filling amount data from the automatic weighing machine of the automatic filling machine; In step S1, the vibroflotation and vibration stage is a stage in the construction process of the vibroflotation gravel pile, and the vibroflotation construction stage includes the hole forming stage, the hole cleaning stage, the vibroflotation and vibration stage, the pile pulling stage, and the vibroflotation and vibration stage in sequence. In the construction process of the vibroflotation gravel pile, the amplitude characteristics of the real-time construction current time curve are used to distinguish the construction stages.

[0006] During the construction of the vibroflotation gravel pile, the construction equipment has the characteristics of reciprocating "up-down" in space and fluctuation of current, and the signal time-frequency characteristics and signal amplitude characteristics of the vibration signal will change obviously, so the signal time-frequency characteristics and signal amplitude characteristics can be used to distinguish the construction stages.

[0007] In a specific implementation, the pore-forming stage starts with a slow decrease of the vibrator depth to the designed depth, which is a step change in detail; the hole cleaning stage is characterized by a large "up-down" of the vibrator; the vibrator repeatedly performs a small "up-down-hold" in the vibrator hold stage, the vibrator current increases with the increase of the depth (down), decreases with the decrease of the depth (up), and is stable when the vibrator depth is stable, and the current periodically changes obviously; the vibrator stops working in the pile pulling-out stage, and the current is zero.

[0008] Step S2, draw the real-time construction depth-time curve, the real-time construction current-time curve and the real-time construction filler amount-time curve according to the data obtained in step S1 respectively; Step S3, identify the time period in which the depth remains unchanged for several seconds continuously as a pseudo-vibration hold working section in the real-time construction depth-time curve, and mark the pseudo-vibration hold working section on the real-time construction current-time curve and the real-time construction filler amount-time curve synchronously; Step S4, identify the filler operation in the real-time construction filler amount-time curve, regard each stage between two adjacent filler operations as a vibration hold large section, and mark the vibration hold large section on the real-time construction current-time curve and the real-time construction depth-time curve synchronously; Step S5, each vibration hold large section contains one or more pseudo-vibration hold working sections, identify the corresponding lower insertion point and upper pulling-out point of each vibration hold large section based on the amplitude change characteristics of the real-time construction current-time curve near each pseudo-vibration hold working section in each vibration hold large section, and obtain the construction depth corresponding to each lower insertion point and upper pulling-out point.

[0009] Step S5 can be specifically divided into the following two steps: Step S51, for each vibration hold large section, identify the time node of the first amplitude mutation near the first pseudo-vibration hold working section after the start of the current vibration hold large section as the lower insertion point, and identify the time node of the last amplitude mutation near the last pseudo-vibration hold working section before the end of the current vibration hold large section as the upper pulling-out point based on the amplitude change characteristics of the real-time construction current-time curve near each pseudo-vibration hold working section in the current vibration hold large section; the amplitude change characteristics of the real-time construction current-time curve near the pseudo-vibration hold working section are specifically that the sign of the slope of the current-time curve changes at a certain time node.

[0010] Step S52, mark the lower insertion point and the upper pulling-out point on the real-time construction depth-time curve synchronously, and obtain the construction depth corresponding to each lower insertion point and upper pulling-out point.

[0011] Step S6, calculate the lateral extrusion range of the gravel filler and the soil compactness between piles after the end of each vibration hold large section according to the construction depth of step S5.

[0012] Step S6 can be specifically divided into the following two steps: Step S61, according to the construction depth of step S5, the lateral extrusion range of the gravel filling after each vibroflotation and vibration remaining large section is calculated, that is, the pile diameter formed after each vibroflotation and vibration remaining large section is calculated, and the pile forming mode model of each vibroflotation and vibration remaining large section is constructed in turn; specifically, the initial average hole diameter of each vibroflotation and vibration remaining large section is calculated according to the following formula : The average hole diameter after each vibroflotation and vibration remaining large section is calculated as follows : In the formula, is the filling amount; is the lower insertion point depth of the first pseudo-vibration remaining section of the vibroflotation and vibration remaining large section; is the upper pulling point depth of the last pseudo-vibration remaining section of the vibroflotation and vibration remaining large section; is the upper pulling point depth of the last pseudo-vibration remaining section of the last vibroflotation and vibration remaining large section.

[0013] Step S62, based on the pile diameter formed by each vibroflotation and vibration remaining large section, the compaction degree of the soil between piles after each vibroflotation and vibration remaining large section is calculated to evaluate the reinforcement effect of the soil between piles; specifically, the compaction degree of the soil between piles after each vibroflotation and vibration remaining large section is calculated as follows : In the formula, is the compaction degree of the soil between piles before each vibroflotation and vibration remaining large section; is the processing area borne by one pile vibroflotation and compaction, is the average hole diameter after each vibroflotation and vibration remaining large section, is the initial average hole diameter of each vibroflotation and vibration remaining large section.

[0014] The present application first divides the pseudo-vibration section according to the depth-time curve of the vibroflotation device, determines the key stage according to the filling amount-time curve, and finally finds the time nodes of the insertion and pulling of the gravel pile of the vibroflotation device through the amplitude change rule of the current-time curve, judges the settlement difference of the gravel filling amount before and after vibration, estimates the pile forming mode, evaluates the change of the compaction degree of the soil between piles before and after reinforcement, and finally obtains the average compaction degree of the soil between piles of the reinforced foundation. The method of the present application calculates and evaluates the pile forming mode and the compaction effect of the soil between piles through construction data.

[0015] The application can realize the estimation of the pile form in the encryption process of the vibrator and further evaluate the soil density between piles through the real-time collected construction information, perfect the pile diameter calculation method, and increase the path for timely and effective reinforcement effect evaluation. The application has the advantages of fast evaluation speed, high accuracy, and the like, and is suitable for reinforcement effect evaluation of the ground treated by the vibro-replacement stone column method with the down-insertion and up-pulling construction process.

[0016] The application has the following advantages: 1. The application can accurately feedback the transverse compaction and vertical settlement effect of the stone filler through the down-insertion and up-pulling position estimation method of the vibrator in the vibration period, and perfect the existing pile form calculation path.

[0017] 2. The application is suitable for reinforcement effect evaluation of the ground treated by the vibro-replacement stone column method with the down-insertion and up-pulling construction process. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 : Schematic diagram of construction stage division of the vibro-replacement stone column; Figure 2 : Schematic diagram of down-insertion and up-pulling point identification in the vibration period of the vibrator; Figure 3 : Pile form diagram obtained based on the construction data of the example; Figure 4 : Soil density change diagram of each pile in the vibration period in the treatment area of the case. DETAILED DESCRIPTION

[0019] The application will be further described below in combination with the drawings and specific implementation cases. The following implementation cases are only used to illustrate the application and are not used to limit the scope of the application. In addition, it should be understood that those skilled in the art can make various changes or modifications to the application after reading the content taught by the application, and these equivalent forms also fall within the scope defined by the appended claims of the application.

[0020] The content of the application will be specifically described below by taking the construction of the vibro-replacement stone column method as an example: Step S1: Extract the real-time depth, real-time current and real-time construction filler amount data in the vibration period of the vibro-replacement stone column construction process from the vibrator and the automatic filler machine; extract the real-time depth and real-time current data from the built-in system of the vibrator, and extract the real-time construction filler amount data from the automatic weighing machine of the automatic filler machine.

[0021] Step S2: Draw the real-time construction depth time curve, real-time construction current time curve and real-time construction filler amount time curve according to the data obtained in step S1.

[0022] Step S3, identify the time period in which the depth in the real-time construction depth-time curve remains basically unchanged for several seconds as a pseudo-vibration-remaining working section, and mark the pseudo-vibration-remaining working section on the real-time construction current-time curve and the real-time construction filler amount-time curve, that is, find the working section corresponding to the pseudo-vibration-remaining working section on the real-time construction current-time curve and the real-time construction filler amount-time curve; specifically, mark the time period in which the depth in the key construction stage, that is, the densification vibration-remaining stage, remains unchanged for 10 seconds or more as a pseudo-vibration-remaining working section.

[0023] Step S4, identify the filler operation in the real-time construction filler amount-time curve, regard each stage between two adjacent filler operations as a vibration-remaining large section, and mark the vibration-remaining large section on the real-time construction current-time curve and the real-time construction depth-time curve, that is, find the working section corresponding to the pseudo-vibration-remaining working section on the real-time construction current-time curve and the real-time construction depth-time curve, and the filler operation in the construction filler amount-time curve is judged by the stepwise increase of the curve; Specifically, refer to the filler amount-time curve to obtain the loose volume of the gravel filler and the feeding time node, divide the corresponding vibration-remaining large section, and correspond the time node to the pseudo-vibration-remaining working section to identify the immediately preceding down-insertion point before the vibration-remaining large section and the immediately following up-pulling point after the vibration-remaining large section.

[0024] Step S5, each vibration-remaining large section contains one or more pseudo-vibration-remaining working sections, based on the amplitude change characteristics of the real-time construction current-time curve near each pseudo-vibration-remaining working section in each vibration-remaining large section, identify the corresponding down-insertion point and up-pulling point of each vibration-remaining large section, and obtain the respective corresponding construction depth of the down-insertion point and the up-pulling point.

[0025] Unlike the real vibration-remaining section, the pseudo-vibration-remaining section only considers the depth change characteristics without considering whether the current reaches the densification current; the vibration-remaining large section often contains multiple pseudo-vibration-remaining sections.

[0026] Specifically, it can be divided into the following two steps: Step S51, for each vibration-remaining large section, based on the amplitude change characteristics of the real-time construction current-time curve near each pseudo-vibration-remaining working section in the current vibration-remaining large section, that is, before and after the reinforcement, identify the first amplitude mutation time node near the first pseudo-vibration-remaining working section after the start of the current vibration-remaining large section as the down-insertion point, and the last amplitude mutation time node near the last pseudo-vibration-remaining working section before the end of the current vibration-remaining large section as the up-pulling point; the amplitude change characteristics of the real-time construction current-time curve near the pseudo-vibration-remaining working section are specifically manifested as: at a certain time node, the slope of the current-time curve changes in sign, that is, the slope of the current-time curve before the current time node is positive, and the slope of the current-time curve after the current time node is negative. In specific implementation, the point at which the slope of the current-time curve changes by more than 2 is identified as a mutation point.

[0027] Step S52, the lower insertion point and the upper pulling point are marked on the real-time construction depth-time curve to obtain the respective construction depths of the lower insertion point and the upper pulling point.

[0028] Generally, the first current mutation position before and after the large vibration remaining vibration section is taken as the lower insertion and upper pulling position on the real-time construction current-time curve, and is corresponded with the real-time construction depth-time curve.

[0029] Step S6, according to the construction depth of step S5, the lateral extrusion range of the gravel filler after each vibration remaining vibration section is ended, i.e. the reinforced site, and the soil density between piles are calculated, and the reinforcement effect of the soil between piles is evaluated, which can be specifically divided into the following two steps: Step S61, according to the construction depth of step S5, the lateral extrusion range of the gravel filler after each vibration remaining vibration section is ended, i.e. the pile diameter formed after each vibration remaining vibration section is calculated, and the pile forming mode model of each vibration remaining vibration section is drawn in turn; the initial average hole diameter before each filler remaining vibration is expanded according to the following formula : The average hole diameter after each vibration remaining vibration section is expanded, i.e. after each filler remaining vibration is expanded according to the following formula : In the formula, is the amount of filler; is the depth of the lower insertion point of the first pseudo remaining vibration section of the vibration remaining vibration section; is the depth of the upper pulling point of the last pseudo remaining vibration section of the vibration remaining vibration section; is the depth of the upper pulling point of the last pseudo remaining vibration section of the previous vibration remaining vibration section.

[0030] Step S62, based on the pile diameter formed by each vibration remaining vibration section and the pile forming mode model, the soil density between piles after each vibration remaining vibration section is calculated to evaluate the reinforcement effect of the soil between piles; the soil density between piles after each vibration remaining vibration section is calculated according to the following formula , i.e. the soil density between piles of the reinforced site: In the formula, is the soil density between piles before each vibration remaining vibration section; is the processing area borne by the vibration compaction of one pile, which is related to the pile arrangement form, is the average hole diameter after each vibration remaining vibration section, is the initial average hole diameter of each vibration remaining vibration section.

[0031] In the implementation, the use process of the method is specifically explained by taking a water conservancy and hydropower engineering vibroflotation stone column treatment as an example. The implementation case is only used to illustrate the present application and is not used to limit the scope of the present application.

[0032] The implementation case adopts a half guide hole construction process, and a total of 7 stone columns are constructed, the pile forming depth is 80 m, and the initial pore ratio after depth weighting is 0.72. The guide hole depth is 18 m, the guide hole diameter is 0.8 m, the pile spacing is 2.5 m, the equivalent influence circle diameter of a single pile is 2.625 m, and three rows of plum blossom type piles are adopted. The construction data monitored by the vibroflotation equipment is obtained and processed and analyzed.

[0033] According to formula (1), the pile diameters of each vibration remaining section of the 7 stone columns in the treatment area are as shown in formula (1); according to formula (2), the pile soil pore ratio of the corresponding influence area of each vibration remaining section of the 7 stone columns in the treatment area is significantly reduced, as shown in formula (2); according to formula (3), the pore ratio of the non-guide hole area of the 7 stone columns in the treatment area is 0.45 according to the remaining vibration depth weighting, and the compaction degree of the pile soil is significantly improved. Figure 3 Figure 4

[0034] The above-described embodiments only represent several implementation manners of the present application, the description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.​​

Claims

1. A method for evaluating the pile formation and the soil density between piles based on the construction data of vibro stone columns, characterized in that, The method comprises the following steps: Step S1, extracting real-time depth, real-time current and real-time construction filler amount data of the vibration remaining stage in the construction process of the vibroflotation stone pile from the vibrator and the automatic filler; Step S2, drawing a real-time construction depth time curve, a real-time construction current time curve and a real-time construction filler amount time curve according to the data obtained in step S1 respectively; Step S3, identifying a time period in which the depth remains unchanged for consecutive seconds in the real-time construction depth time curve as a pseudo-vibration remaining work section, and synchronously marking the pseudo-vibration remaining work section on the real-time construction current time curve and the real-time construction filler amount time curve; Step S4, identifying filler operations in the real-time construction filler amount time curve, regarding each stage between two adjacent filler operations as a vibroflotation vibration remaining large section, and synchronously marking the vibroflotation vibration remaining large section on the real-time construction current time curve and the real-time construction depth time curve; Step S5, each vibroflotation vibration remaining large section contains one or more pseudo-vibration remaining work sections, based on the amplitude variation characteristics of the real-time construction current time curve near each pseudo-vibration remaining work section in each vibroflotation vibration remaining large section, identifying the corresponding lower insertion point and upper pulling point of each vibroflotation vibration remaining large section, and obtaining the respective corresponding construction depth of the lower insertion point and the upper pulling point; Step S6, according to the construction depth of step S5, calculating the lateral extrusion range of the gravel filler and the soil compactness between piles after the end of each vibroflotation vibration remaining large section.

2. The method for evaluating the pile shape and soil density between piles based on the construction data of the vibroflotation stone column according to claim 1, characterized in that, The step S1 is specifically: extracting real-time depth and real-time current data from the built-in system of the vibrator, and extracting real-time construction filler amount data from the automatic weighing machine of the automatic filler.

3. The method for evaluating the pile shape and soil density between piles based on the construction data of the vibro-replacement stone column according to claim 1, characterized in that, The step S5 is specifically: Step S51, for each vibroflotation vibration remaining large section, based on the amplitude variation characteristics of the real-time construction current time curve near each pseudo-vibration remaining work section in the current vibroflotation vibration remaining large section, identifying the time node of the first amplitude mutation near the first pseudo-vibration remaining work section after the start of the current vibroflotation vibration remaining large section as the lower insertion point, and the time node of the last amplitude mutation near the last pseudo-vibration remaining work section before the end of the current vibroflotation vibration remaining large section as the upper pulling point; Step S52, synchronously marking the lower insertion point and the upper pulling point on the real-time construction depth time curve to obtain the respective corresponding construction depth of the lower insertion point and the upper pulling point.

4. The method for evaluating the pile shape and soil density between piles based on the construction data of the vibro-replacement stone column according to claim 1, characterized in that, The step S6 is specifically: Step S61, according to the construction depth of step S5, calculating the lateral extrusion range of the gravel filler after the end of each vibroflotation vibration remaining large section, i.e. calculating the pile diameter formed after the end of each vibroflotation vibration remaining large section, and sequentially constructing the pile forming mode model of each vibroflotation vibration remaining large section; Step S62, based on the pile diameter formed by each vibroflotation vibration remaining large section and the pile forming mode model, calculating the soil compactness between piles after the end of each vibroflotation vibration remaining large section.

5. The pile forming mode and soil compactness between piles evaluation method based on the construction data of the vibroflotation stone pile according to claim 3, characterized in that: In step S51, the amplitude variation characteristics of the real-time construction current time curve near the pseudo-vibration remaining work section are specifically that the sign of the slope of the current time curve changes at a certain time node.

6. The method for evaluating the pile formation and soil density between piles based on the construction data of vibroflotation stone column according to claim 1, characterized in that: In the step S1, the vibroflotation and vibration stage is a stage in the construction process of the vibroflotation stone column, and the vibroflotation construction stage sequentially includes a hole forming stage, a hole cleaning stage, the vibroflotation and vibration stage, a protective cylinder pulling stage, and the vibroflotation and vibration stage in time sequence; in the construction process of the vibroflotation stone column, the amplitude characteristics of the real-time construction current time curve are used to distinguish the construction stages.

7. The method for evaluating the pile formation and soil density between piles based on the construction data of vibroflotation stone column according to claim 4, characterized in that: The initial average pore diameter of each shock-remaining large section is calculated according to the following formula in step S61 : The average pore size at the end of each shock dwell section was calculated as follows : wherein, is the amount of filler; is the lower insertion point depth of the first pseudo-standby section of the vibration-standby large section; is the upper extraction point depth of the last pseudo-standby section of the vibration-standby large section; is the upper extraction point depth of the last pseudo-standby section of the previous vibration-standby large section.

8. The method for evaluating the pile formation and soil density between piles based on the construction data of vibroflotation stone column according to claim 4, characterized in that: In step S62, the soil density between the piles after the completion of the each vibration and vibration damping section is calculated as follows : wherein, is the soil density before the start of each vibroflotation residual section; is the treatment area of one vibroflotation, is the average pore size after the end of each vibroflotation residual section, is the initial average pore size of each vibroflotation residual section.

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