Construction method of vibro-replacement stone column based on effective vibration density times

Abstract

The present application belongs to the technical field of composite foundation construction, and particularly relates to a construction method of a vibro-replacement gravel pile based on effective vibration and compaction times. In the construction process of the vibro-replacement gravel pile, the pile body is equally divided into depth units of equal length, and the effective vibration and compaction times of each depth unit are calculated and analyzed by using the real-time monitored depth data of the vibrator, the current data of the vibrator and the cumulative filling amount data during the construction process. According to the analysis result, the depth unit with an effective vibration and compaction time less than 1 is supplemented with vibration and compaction until the effective vibration and compaction times of all the depth units are not less than 1, and the construction of the pile body is completed. The present application can realize in-process quality control for the vibro-replacement gravel pile in large-area construction, and can further improve the quality qualified guarantee rate of the vibro-replacement gravel pile construction for the vibro-replacement gravel pile not subjected to sampling inspection. The method for calculating the effective vibration and compaction times in the present application is easy to form a programmed operation process, and can realize full-automatic analysis through system development.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of composite foundation construction, and particularly relates to a construction method of a vibro-replacement gravel pile based on effective vibration and compaction times. BACKGROUND

[0002] The vibro-replacement gravel pile is an important engineering measure for soft soil foundation treatment, which can replace the original soft soil foundation by gravel and compact the soil by vibration to achieve the effects of reinforcing the foundation, improving the drainage and improving the anti-seismic liquefaction weakening ability. The vibro-replacement gravel pile is a concealed project, and the construction quality control is mainly realized by formulating reasonable construction parameters before construction and sampling detection according to the specification after construction. In the construction process, due to the characteristics of the concealed project, the deviation of the operation personnel in the execution of the construction parameters is difficult to be found in real time, and the actual pile quality is difficult to be grasped in real time. Once the unqualified pile is found in the sampling detection after construction, the pile needs to be reworked, which causes a large amount of economic loss. In addition, there is a risk that the unqualified pile is not found in the sampling detection. Once the unqualified pile is not found, the overall effect of the foundation treatment and the safety of the upper structure may be affected. Developing a vibro-replacement gravel pile construction method that can realize in-process quality control can effectively improve the construction quality guarantee rate of the vibro-replacement gravel pile. SUMMARY

[0003] The purpose of the application is to solve the in-process quality control problem in the construction process of a large-area vibro-replacement gravel pile, and to provide a vibro-replacement gravel pile construction method based on effective vibration and compaction times.

[0004] To achieve the above-mentioned purpose, the technical scheme of the application is as follows:

[0005] A vibro-replacement gravel pile construction method based on effective vibration and compaction times, in the construction process of the vibro-replacement gravel pile, the pile body is divided into depth units with equal lengths, the vibration and compaction times of each depth unit are calculated and analyzed by using the real-time monitored vibration and compaction depth data, vibration and compaction current data and cumulative filling amount data in the construction process, the depth unit with an effective vibration and compaction time less than 1 is supplemented and compacted according to the analysis result, and the construction of the pile body is ended until the effective vibration and compaction times of all depth units are not less than 1.

[0006] Specifically includes the following steps:

[0007] S1: install a digital construction monitoring system for the vibro-replacement gravel pile construction equipment, so that the digital construction monitoring system records the construction data in the construction process of the vibro-replacement gravel pile in real time at a frequency of 1 second per record, and each data at least contains the cumulative filling amount, the real-time current and the real-time depth of the current construction pile position, so that the data at the nth second contains the cumulative filling amount V n of the current pile position at the nth second, the real-time current I nReal-time depth d of the vibrator at the n th second n ;

[0008] S2: divide the vibro-replacement pile with length L into m depth units, then the height Δz of each depth unit is calculated as follows:

[0009] Δz = L / m (1)

[0010] wherein Δz: length of each depth unit; L: length of the pile; m: number of segments;

[0011] At this time, the pile body is divided into m depth units from the top z = 0 to the bottom z = L, denoted as z i , z i The depth interval represented by z

[0012] S3: before the formal construction of the vibro-replacement pile, a trial pile test is carried out, and the test pile is quality detected according to the design requirements and the specification requirements, the reasonable single filling amount Δm, the reasonable vibro-replacement segment length ΔL and the minimum vibro-replacement current I min and the shortest vibration remaining time t min suitable for the site engineering geological conditions are determined through the construction data of the trial pile test and the pile body quality detection data, and the minimum vibration remaining time t Δz of each depth unit is calculated as follows:

[0013] t Δz = t min Δz / ΔL (2)

[0014] S4: for each pile, the formal construction is first completed with the preliminary construction procedure;

[0015] S5: fill the stone according to the reasonable single filling amount Δm determined by the trial pile test;

[0016] S6: sink the vibrator and start the vibration, and carry out the stone vibro-replacement construction according to the reasonable vibro-replacement segment length ΔL and the minimum vibro-replacement current I min and the shortest vibration remaining time t min determined by the trial pile test;

[0017] S7: for each depth unit z i in the filled depth range, calculate the effective vibro-replacement times thereof:

[0018] S8: feed back the calculation results of S7 to the site operator, and immediately carry out the supplementary vibro-replacement for the depth units with the effective vibro-replacement times less than 1;

[0019] S9: Repeat S7 and S8 until the effective vibration density number of all depth units of the filled material is not less than 1, and judge that the construction quality of the filled depth range meets the requirements.

[0020] S10: Repeat S5 to S9 until the entire pile construction is completed.

[0021] The digital construction monitoring system described in S1 includes sensors, a display screen, and related software. The sensors include at least a vibratory compactor depth monitoring sensor, a vibratory compactor current monitoring sensor, and a filler quantity monitoring sensor.

[0022] The selection of the number of segments m in S2 ensures that Δz is not greater than the effective vibration compaction influence range in the depth direction after the vibratory beater starts vibrating.

[0023] The preliminary construction procedures in S4 include construction preparation, drilling to the designed depth, and hole cleaning.

[0024] The calculation of the effective vibration density in S7 includes the following steps:

[0025] S7-1: Analyze the data recorded by the digital construction monitoring system line by line, removing all V... n Data with a value of 0;

[0026] S7-2: Plot a curve with time on the horizontal axis and the real-time depth of the vibratory impactor on the vertical axis, and find all the peaks and troughs in the curve;

[0027] S7-3: Divide the curve drawn in step S7-2 into segments according to the trough positions and form analysis units. The range between two adjacent troughs is one analysis unit U. j Where j is the analysis unit number;

[0028] S7-4: For any element U in step S7-3 j Find time points a and b such that, from time a to time b, equation I is always satisfied. n ≥I min This forms a new analysis unit U. a,b , such as U j If no time points a and b that meet the requirements can be found in the analysis, then the analysis unit is an invalid analysis unit.

[0029] S7-5: For the analysis unit U formed in step S7-4 a,b Calculate the duration t respectively a,b Maximum depth d nmax Minimum depth d nmin where n∈[a,b];

[0030] S7-6: For each depth unit z i ∈[dnmin ,d nmax If both equations (3) and (4) are satisfied, then z i The effective vibration density increase is 1 time, otherwise z i The effective vibration density number does not increase;

[0031] t a,b ≥t min (3)

[0032] t a,b Δz / (d nmax -d nmin )≥t Δz (n∈[a,b]) (4)

[0033] S7-7: Complete all analysis units U following the methods and steps outlined in S7-4 to S7-6. j After analysis and calculation, all depth elements z can be obtained. i The effective number of vibration densities.

[0034] The beneficial effects of this invention are as follows:

[0035] (1) For vibratory compaction of stone piles with large-area construction, in-process quality control can be achieved. By calculating the effective number of vibrations within the depth range of the filled material during construction and feeding it back to the operators, the operators can promptly supplement the vibration in areas with insufficient vibration, i.e. depth units with an effective number of vibrations less than 1, which can effectively ensure the construction quality of the pile body.

[0036] (2) The vibratory stone crushing piles completed by the construction method of the present invention can ensure that the effective compaction times of all depth units of the vibratory stone crushing piles that have not been sampled are not less than 1, which can further improve the quality qualification rate of large-area vibratory stone crushing pile construction.

[0037] (3) The method for calculating the effective vibration density in this invention is easy to form a programmed operation process and can be fully automated through system development. Detailed Implementation

[0038] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0039] Example

[0040] Taking the construction of a single pile in a large-scale vibratory compaction stone pile project as an example, the vibratory compaction stone pile in this project is designed to be 10m long. After the vibratory compactor is turned on, the effective vibration compaction range is within 1m of the end of the vibratory compactor in the depth direction.

[0041] In actual construction, the construction of vibro-replacement stone piles is carried out according to the following steps:

[0042] S1: A digital construction monitoring system is installed for the vibro-replacement stone pile construction equipment, including a vibro-replacement depth monitoring sensor, a vibro-replacement current monitoring sensor, a filler quantity monitoring sensor, a display screen and related software, so that the digital construction monitoring system records the construction data in the construction process of the vibro-replacement stone pile in real time at a frequency of 1 second per record. Each data contains the cumulative filler quantity of the current pile site, the real-time current of the vibro-replacement and the real-time depth. The data of the nth second contains the cumulative filler quantity V n of the current pile site at the nth second, the real-time current I n of the vibro-replacement at the nth second and the real-time depth d n of the vibro-replacement at the nth second;

[0043] S2: The vibro-replacement stone pile is divided into 20 depth units. The length Δz of each depth unit is calculated according to the following formula:

[0044] Δz=L / m=10 / 20=0.5m<1m (1)

[0045] The selection of the number of segments m ensures that Δz is not greater than the effective vibration and compaction influence range of the vibro-replacement in the depth direction after the vibro-replacement is turned on. The above calculation result meets the requirements.

[0046] At this time, the pile body is equally divided into 20 depth units from the top (z=0) to the bottom (z=10m), denoted as z i . z i represents the depth interval from i·Δz to (i+1)·Δz, where i=0, 1, 2,…, 19.

[0047] S3: Before the formal construction of the vibro-replacement stone pile, a test pile is formed, and the quality of the test pile is detected according to the design requirements and the specification requirements. The reasonable single filler quantity Δm suitable for the site engineering geological conditions is determined as 1.5t through the construction data of the test pile and the pile body quality detection data, the reasonable vibration and compaction segment length ΔL is 1m, the minimum vibration and compaction current corresponding thereto is I min , the minimum remaining vibration time t min is 8s, and the minimum remaining vibration time t Δz of each depth unit is:

[0048] t Δz =t min Δz / ΔL=8×0.5 / 1=4s (2)

[0049] S4: For the vibro-replacement stone pile in this example, during the formal construction, the pre-construction procedures such as construction preparation, hole making to the design depth and hole cleaning are first completed;

[0050] S5: Fill 1.5t stone into the hole;

[0051] S6: Sink the vibrator and start vibration, and conduct vibration compaction construction on the filled stone according to the parameters that the vibration current is not less than 150A and the vibration is kept for not less than 8s in each 1m depth range;

[0052] S7: For each depth unit z i in the filled depth range, calculate the effective vibration compaction times according to the following method:

[0053] S7-1: Analyze the data recorded by the digital construction monitoring system piece by piece, and remove all data with V n =0;

[0054] S7-2: Draw a curve with time as the horizontal axis and real-time depth of the vibrator as the vertical axis, and find all the peaks and troughs in the curve;

[0055] S7-3: Segment the curve drawn in step S7-2 according to the positions of the troughs and form analysis units, and the range between two adjacent troughs is an analysis unit U j , where j is the analysis unit number;

[0056] S7-4: For any unit U j in step S7-3, find time point a and time point b, so that during the time from a to b, formula I n ≥150A is always satisfied, and form a new analysis unit U a,b , such as U j If time point a and time point b that meet the requirements cannot be found in U j , the analysis unit is an invalid analysis unit;

[0057] S7-5: For the analysis unit U a,b formed in step S7-4, calculate the duration t a,b , the maximum depth d nmax , and the minimum depth d nmin , respectively, where n∈[a,b];

[0058] S7-6: For each depth unit z i ∈[d nmin ,d nmax ], if formulas (3) and (4) are both satisfied, the effective vibration compaction times of z i are increased by 1, otherwise the vibration compaction times of z i are not increased;

[0059] t a,b ≥8s (3)

[0060] t a,b ×0.5 / (d nmax-d nmin ) ≥ 4 s (n ∈ [a, b]) (4)

[0061] S7-7: According to the method and steps of S7-4 to S7-6, after the analysis calculation of all analysis units U is completed, the effective tamping times of all depth units z j can be obtained. i

[0062] S8: The calculation results of S6 are fed back to the on-site operators, and for all depth units with effective tamping times less than 1, immediate supplementary tamping is carried out;

[0063] S9: Repeat S7 and S8 until the effective tamping times of all filled depth units are not less than 1, and determine that the construction quality of the filled depth range meets the requirements;

[0064] S10: Repeat S5 to S9 until the entire pile construction is completed.​

Claims

1. A construction method of a vibro-replacement stone column based on effective number of vibrations, characterized in that, In the construction process of the vibro-replacement stone pile, the pile body is equally divided into depth units with equal length, the effective vibration and compaction times of each depth unit are calculated and analyzed by using the real-time monitored depth data of the vibrator, the vibrator current data and the cumulative filling amount data in the construction process, the depth units with effective vibration and compaction times less than 1 are supplemented with vibration and compaction according to the analysis results, and the construction of the pile body is ended until the effective vibration and compaction times of all depth units are not less than 1; Specifically, the method comprises the following steps: S1: install a digital construction monitoring system for the vibro-replacement stone pile construction equipment, so that the digital construction monitoring system records the construction data in the vibro-replacement stone pile construction process in real time at a frequency of 1 second per record, and each piece of data at least contains the cumulative filling amount of the current construction pile site, the real-time current of the vibrator, and the real-time depth, so that the data of the nth second contains the cumulative filling amount V n of the current pile site at the nth second, n the real-time current I n of the vibrator at the nth second, and n the real-time depth d n of the vibrator at the nth second; S2: the vibro-replacement stone pile with a pile length of L is equally divided into m depth units, and the height Δz of each depth unit is calculated according to the following formula: Δz = L / m (1) Wherein, Δz: the length of each depth unit; L: the pile length; m: the number of segments; At this time, the pile body is equally divided into m depth units from the top z = 0 to the bottom z = L, denoted as z i Then z i The depth interval represented by i·Δz to (i+1)·Δz, where i = 0, 1, 2, …, m-1; S3: Before the formal construction of the vibro-replacement stone pile, a test pile is formed, and the quality of the test pile is detected according to the design requirements and the specification requirements. The reasonable single filling amount Δm, the reasonable vibration compaction section length ΔL and the minimum vibration compaction current I corresponding thereto suitable for the on-site engineering geological conditions are determined through the construction data of the test pile forming test and the pile body quality detection data min and the shortest vibration time t min , and the minimum vibration time t of each depth unit is calculated according to the following formula Δz : t Δz =t min Δz / ΔL (2) S4: for each pile, the pre-construction process is first completed in the formal construction; S5: the reasonable single filling amount Δm of stone determined by the trial pile test is filled; S6: sink the vibrator and start vibration, according to the reasonable vibration length ΔL and the minimum vibration current I corresponding to it determined by the trial pile test min and the shortest vibration time t min Carry out stone vibration compaction construction; S7: for each depth unit in the filled depth range, the effective vibration and compaction times are calculated, which specifically comprises the following steps: S7-1: Analyze the data recorded by the digital construction monitoring system piece by piece, remove all data with V n = 0; S7-2: a curve is drawn with time as the horizontal axis and the real-time depth of the vibrator as the vertical axis, and all the wave crests and troughs in the curve are found out; S7-3: segment the curve plotted in step S7-2 according to the positions of the troughs and form analysis units, then the range between two adjacent troughs is one analysis unit U j where j is the analysis unit number; S7-4: For any analysis unit U in step S7-3 j , find time point a and time point b, so that during the time from a to b, formula I is always satisfied n ≥ I min , form a new analysis unit U a,b , such as U j If time point a and time point b that meet the requirements cannot be found in U, the analysis unit is an invalid analysis unit; S7-5: For the analysis unit U formed in step S7-4 a,b , respectively, the duration t a,b , the depth maximum d nmax , the depth minimum d nmin , wherein n ∈ [a, b]; S7-6: For each depth unit z i ∈ [d nmin , d nmax ], if both equation (3) and equation (4) are satisfied, then the effective vibration density of z i increases by 1, otherwise the effective vibration density of z i does not increase. t a,b ≥t min (3) t a,b Δz / (d nmax -d nmin )≥t Δz (n∈[a,b]) (4) S7-7: After all the analysis units U are completed according to the methods and procedures of S7-4 to S7-6, the effective vibration frequency of all the depth units z j can be obtained. i ​ S8: the calculation results of S7 are fed back to the site operators, and the depth units with effective vibration and compaction times less than 1 are immediately supplemented with vibration and compaction; S9: S7 and S8 are repeated until the effective vibration and compaction times of all filled depth units are not less than 1, and it is judged that the construction quality of the filled depth range meets the requirements; S10: S5 to S9 are repeated until the construction of the whole pile is completed.

2. The construction method of the vibratory stone column based on the effective number of vibrations according to claim 1, characterized in that, The digital construction monitoring system in S1 comprises sensors, a display screen and related software, wherein the sensors at least include a vibrator depth monitoring sensor, a vibrator current monitoring sensor and a filling amount monitoring sensor.

3. The construction method of the vibratory stone column based on the effective number of vibrations according to claim 1, characterized in that, In S2, the number of segments should be selected to ensure that Δz is not greater than the effective vibration and compaction influence range of the vibrator in the depth direction after the vibrator is turned on.

4. The construction method of the vibratory stone column based on the effective number of vibrations according to claim 1, characterized in that, The pre-construction process in S4 includes construction preparation, hole making to the design depth and hole cleaning.