A calculation method for the filling coefficient of gravel piles

Abstract

The present invention discloses a calculation method for the filling coefficient of a gravel pile, which includes the following steps: Step 1, the gravel pile construction is carried out in the following stages: vibrating and sinking the pile pipe → adding materials into the pile pipe → staying at the pile bottom → pulling out the pile pipe → completion of pipe pulling; Step 2, record the data of the whole process of gravel pile construction in real time, including the construction time, pile tip elevation and material level in the pipe at each stage; Step 2, draw a relationship curve between the construction time and the pile tip elevation according to the recorded data to obtain the change value of the pile tip elevation per unit time, which is the pipe pulling speed. At the same time, draw a relationship curve between the construction time and the material level in the pipe according to the recorded data to obtain the change value of the material level in the pipe per unit time, which is the feeding speed; Step 3, divide the feeding speed in the same unit time period by the pipe pulling speed to obtain the filling coefficient in this unit time. The present invention can dynamically reflect the differential distribution of the filling coefficient of the whole pile body during the construction process of the gravel pile in real time, which is convenient for controlling the quality of the gravel pile.

Description

Technical Field

[0001] The present invention relates to a calculation method for the filling coefficient of a gravel pile. Background Art

[0002] The gravel pile is a composite foundation reinforcement pile of the compaction pile type, mainly used for soft soil foundation treatment. The gravel pile uses methods such as vibration, impact, or water jetting to first vertically mechanically form a hole in the soft foundation, and then fill it with hard granular materials such as gravel, cobblestone, or slag and vibrate it densely to form a dense pile body composed of large-diameter sand and gravel or gravel. This composite foundation reinforcement pile is economical, simple, and effective.

[0003] For a gravel pile, the filling coefficient refers to the ratio of the actual amount of gravel poured into a pile to the volume of the pile body calculated based on the outer diameter of the pile pipe. The filling coefficient of a gravel pile is generally specified to be 1.0 - 1.3. The main indicators of a gravel pile are the conversion rate and the continuity of the pile body for vertical drainage. The design requires that the pile body formation continuity of the gravel pile be consistent, that is, the filling coefficient from the pile bottom to the pile top be consistent. The traditional calculation method for the filling coefficient is to calculate it by the ratio of the volume of gravel used for a single pile to the volume of the designed pile body. This calculation method can only calculate the overall filling coefficient of the entire pile and cannot reflect the pile body formation continuity. In the middle and lower regions of the pile body, due to the active earth pressure and passive earth pressure generated by the compaction effect, the discharge amount of the pile pipe bottom is less, or even unable to discharge, under the condition that there is no external force in the pipe, resulting in a smaller filling coefficient in the middle and lower regions of the pile body; in the middle and upper regions of the pile body, due to the reduction of the external soil layer density and the smaller earth pressure, the pile pipe discharges more material, resulting in an excessive filling coefficient in the middle and upper regions of the pile body. Especially for the gravel piles at sea, without auxiliary measures, it is difficult to guarantee the quality of the formed pile, and the continuity of the pile body after pile formation is difficult to meet the design requirements. Therefore, in order to control the pile body continuity of the gravel pile, it is necessary to dynamically measure the filling coefficient of the gravel pile in real time during the feeding process. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a calculation method for the filling coefficient of a gravel pile, which can calculate the filling coefficient in real time and dynamically through the pile tip elevation and the material level in the pipe measured by the gravel pile information system, and can reflect the differential distribution of the filling coefficient of the entire pile body during the construction process of the gravel pile in real time and dynamically, so as to guide the construction quality control of the gravel pile.

[0005] The purpose of the present invention is achieved as follows: A calculation method for the filling coefficient of a gravel pile, comprising the following steps:

[0006] Step 1, conduct gravel pile construction according to the following stages: vibrating and sinking the pile pipe → adding material to the pile pipe → staying at the pile bottom → pulling out the pile pipe → completion of pipe pulling;

[0007] Step 2: Record the data of the entire process of vibroflotation stone column construction in real time, including the construction time, pile tip elevation, and in-pipe material level at each stage.

[0008] Step 2: Draw a relationship curve between the construction time and the pile tip elevation based on the recorded data to obtain the change value of the pile tip elevation per unit time, which is the pipe extraction speed. At the same time, draw a relationship curve between the construction time and the in-pipe material level based on the recorded data to obtain the change value of the in-pipe material level per unit time, which is the feeding speed.

[0009] Step 3: Divide the feeding speed by the pipe extraction speed within the same unit time period to obtain the filling coefficient for that unit time.

[0010] For the above calculation method of the filling coefficient of the vibroflotation stone column, during the stage of vibrating and sinking the pile pipe, the pile tip elevation gradually decreases from the ground level of 0, and the in-pipe material level is 0; during the stage of adding material to the pile pipe, the pile tip elevation continues to decrease to the design elevation, and the in-pipe material level gradually increases; during the stage of staying at the pile bottom, the pile tip elevation remains unchanged at the design elevation, and the in-pipe material level remains unchanged at the design material level; during the stage of pulling out the pile pipe, the pile tip elevation gradually rises to the ground level of 0, and the in-pipe material level gradually decreases to 0.

[0011] For the above calculation method of the filling coefficient of the vibroflotation stone column, the unit time is taken as 1 minute.

[0012] The calculation method of the filling coefficient of the vibroflotation stone column of the present invention has the following characteristics:

[0013] 1) By using the vibroflotation stone column information system to measure the pile tip elevation and the in-pipe material level in real time, and drawing the relationship curve between the construction time and the pile tip elevation and the relationship curve between the construction time and the in-pipe material level, the pipe extraction speed and the feeding speed can be obtained, thereby calculating the filling coefficient per unit time of the entire vibroflotation stone column during each construction stage, which can dynamically reflect the difference distribution of the filling coefficient of the entire pile during the construction process of the vibroflotation stone column and solve the problem that the filling coefficient can only be calculated once for the entire pile.

[0014] 2) By comparing the curve slopes of the pipe extraction speed and the feeding speed, it can be easily seen whether the filling coefficient is greater than 1 or less than 1 per unit time, which is beneficial to the process quality control of the vibroflotation stone column.

[0015] 3) It can be used as evidence to reflect the construction quality of the vibroflotation stone column during the process and is used to guide the construction quality control of the vibroflotation stone column. Description of the Drawings

[0016] Figure 1 It is the relationship curve between the construction time and the pile tip elevation and the relationship curve between the construction time and the in-pipe material level drawn when the calculation method of the filling coefficient of the vibroflotation stone column of the present invention is carried out in Step 2. Detailed Embodiment

[0017] The present invention will be further described below in conjunction with the accompanying drawings.

[0018] The calculation method of the filling coefficient of the gravel pile of the present invention includes the following steps:

[0019] Step 1, construct the gravel pile according to the following stages: vibrating and sinking the pile pipe → feeding the pile pipe → staying at the pile bottom → pulling out the pile pipe → completion of pipe pulling; in the stage of vibrating and sinking the pile pipe, the pile tip elevation gradually decreases from the ground 0, and the material level in the pipe is 0; in the stage of feeding the pile pipe, the pile tip elevation continues to decrease to the design elevation, and the material level in the pipe gradually increases; in the stage of staying at the pile bottom, the pile tip elevation remains unchanged at the design elevation, and the material level in the pipe remains unchanged; in the stage of pulling out the pile pipe, the pile tip elevation gradually rises to the ground 0, and the material level in the pipe gradually decreases to 0;

[0020] Step 2, record the data of the whole process of gravel pile construction in real time, including the construction time, pile tip elevation and material level in the pipe at each stage;

[0021] Step 2, draw a relationship curve between the construction time and the pile tip elevation according to the recorded data to obtain the change value of the pile tip elevation per unit time, which is the pipe pulling speed. At the same time, draw a relationship curve between the construction time and the material level in the pipe according to the recorded data (see Figure 1 ), to obtain the change value of the material level in the pipe per unit time, which is the feeding speed; Figure 1 In, the horizontal axis 1 represents the construction time, each space is 1 min, and the vertical axis 2 represents the elevation, each space is 5 m;

[0022] The upper line segments 3, 4, 5, 6 reflect the change of the material level in the pipe; the line segment 3 indicates that in the stage of vibrating and sinking the pile pipe, the material level in the pipe is 0; the line segment 4 indicates that in the stage of feeding the pile pipe, the material level in the pipe gradually increases; the line segment 5 indicates that in the stage of staying at the pile bottom, the material level in the pipe remains unchanged at the design material level; the line segment 6 indicates that in the stage of pulling out the pile pipe, the gravel in the pipe is discharging, and the material level in the pipe gradually decreases until it is 0;

[0023] The lower line segments 7, 8, 9 reflect the change of the pile bottom elevation. The line segment 7 indicates that in the stage of vibrating and sinking the pile pipe and the stage of feeding the pile pipe, the pile tip elevation gradually decreases from the ground 0 to the design elevation. The line segment 8 indicates that in the stage of staying at the pile bottom, the pile tip elevation remains unchanged at the design elevation. The line segment 9 indicates that in the stage of pulling out the pile pipe, the pile tip elevation gradually rises until the ground is 0.

[0024] Step 3, divide the feeding speed in the same unit time period by the pipe pulling speed to obtain the filling coefficient in this unit time.

[0025] Now take the line segment 6 and the line segment 9 as an example to calculate the filling coefficient in a certain unit time in the stage of pulling out the pile pipe. The filling coefficient = the slope of the line segment 6 in the same unit time divided by the slope of the line segment 9 in the same unit time;

[0026] By calculating the filling coefficient per unit time, a conclusion can be drawn on whether the current construction process meets the design requirements. If the calculated filling coefficient is less than 1, it indicates that the current pipe extraction speed is greater than the gravel falling speed, and corresponding process measures need to be taken for rectification;

[0027] In addition, from the turning point time axis of line segment 6 and line segment 9, it can be analyzed whether there is a discharging phenomenon at the same time of the initial pipe extraction, as well as the time lag of discharging.

[0028] The calculation method of the filling coefficient of the gravel pile of the present invention can dynamically reflect the difference distribution of the filling coefficient of the whole pile during the construction process of the gravel pile in real time, and solve the problem that the filling coefficient can only be calculated once for the whole pile.

[0029] The above embodiments are only for illustrating the present invention, rather than limiting the present invention. Those skilled in the relevant technical fields can also make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention, which should be defined by each claim.

Claims

1. A calculation method for the plumpness coefficient of gravel piles, characterized in that, The calculation method includes the following steps: Step 1: The gravel pile construction is carried out in the following stages: vibrating and sinking the pile pipe → feeding the pile pipe → staying at the pile bottom → pulling out the pile pipe → completion of pipe pulling; Step 2: Record the data of the whole process of gravel pile construction in real time, including the construction time, pile tip elevation and in-pipe material level at each stage; Step 2: Draw a relationship curve between the construction time and the pile tip elevation according to the recorded data to obtain the change value of the pile tip elevation per unit time, which is the pipe pulling speed. At the same time, draw a relationship curve between the construction time and the in-pipe material level according to the recorded data to obtain the change value of the in-pipe material level per unit time, which is the feeding speed; Step 3: Divide the feeding speed in the same unit time period by the pipe pulling speed to obtain the filling coefficient in this unit time.

2. The calculation method for the plumpness coefficient of gravel piles according to claim 1, characterized in that, In the stage of vibrating and sinking the pile pipe, the pile tip elevation gradually decreases from the ground level of 0m, and the in-pipe material level is 0m; in the stage of feeding the pile pipe, the pile tip elevation continues to decrease to the design elevation, and the in-pipe material level gradually increases; in the stage of staying at the pile bottom, the pile tip elevation remains unchanged at the design elevation, and the in-pipe material level remains unchanged at the design material level; in the stage of pulling out the pile pipe, the pile tip elevation gradually rises to the ground level of 0m, and the in-pipe material level gradually decreases to 0m.

3. The calculation method for the plumpness coefficient of gravel piles according to claim 1, characterized in that, The unit time is taken as 1 minute.

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