A method for detecting filling body parameters and controlling compaction quality with matching dynamic performance

Abstract

A method for detecting filling body parameters and controlling compaction quality with matching dynamic performance. This method is a compaction quality control method based on real-time detection of filler density during the vibration compaction process of railway subgrade, including making a compression density bucket; filling the density bucket with subgrade filler and weighing it; arranging sensors at the bottom or top position of the density bucket; calculating the density of the density bucket; calculating the filler density during the vibration compaction process; obtaining the maximum dry density of the filler during the vibration compaction process through the heavy hammer compaction test; drying the soil sample in an indoor oven to obtain the moisture content of the filler; obtaining the dynamic compaction coefficient through the dynamic density ρ d and the maximum dry density of the filler; obtaining the time history curve of the dynamic compaction coefficient for different numbers of compaction passes; and monitoring the change law of the compaction state of the filler during the vibration compaction process in real time according to the "High-Speed Railway Design Code", avoiding under-compaction and over-compaction of the vibratory roller.

Description

Technical Field

[0001] The present invention belongs to the technical field of continuous compaction of high-speed railway subgrades. Specifically, the present invention relates to a method for detecting parameters of a filling body with matching dynamic performance and controlling compaction quality. Background Art

[0002] With the increase in the mileage of high-speed railway subgrades in China, the filling work volume of high-speed railway subgrades is bound to increase. At present, how to effectively judge the compaction quality of railway subgrades is an urgent problem to be solved. Therefore, in order to ensure the compaction state of railway subgrades, the control methods currently adopted at home and abroad mainly measure the compaction quality of railway subgrade fillers through methods such as K30, Evd, Ev1, and Ev2. However, these methods indirectly characterize the compaction quality of fillers through the mechanical properties of fillers. The direct detection method for the compaction quality of fillers is the sand replacement method, which belongs to a destructive detection method and has a long test time. It is not suitable for real-time monitoring of the density of fillers during the vibration compaction process.

[0003] Therefore, the present invention makes a self-made longitudinally telescopic settlement density bucket, and arranges acceleration / displacement sensors at the top and bottom of the density bucket to monitor the relative displacement difference between the top and bottom of the telescopic settlement density bucket during the vibration compaction process. According to the mass and volume of the filler, the initial density of the filler is obtained, and the dynamic density change curve of the filler in the density bucket during the vibration compaction process is obtained. An indoor heavy hammer compaction test and a drying method are used to measure the moisture content to obtain the dynamic compaction coefficient. Combining the compaction coefficient requirements for the subgrade surface layer, subgrade bottom layer, and embankment below the subgrade in the "High-Speed Railway Design Code", a vibration compaction rolling process is proposed to avoid over-compaction and under-compaction. Summary of the Invention

[0004] The purpose of the present invention is to use the method of a telescopic density bucket combined with a displacement sensor to real-time monitor the time history curve of the density change of the filler in the density bucket during the vibration compaction process, so as to control the compaction quality of the railway subgrade. The technical solution is as follows:

[0005] A compressible density bucket, comprising a base, a large-diameter cylindrical side part, and a small-diameter cylindrical side part, characterized in that: the large-diameter cylindrical side part and the small-diameter cylindrical side part are filled with subgrade fillers, and the small-diameter cylindrical side is filled with subgrade fillers; the compressible function of the density bucket is realized through a ring-shaped corrugated part and has a lateral constraint and a vertical free compression function.

[0006] A compressible density bucket, comprising a base, a large-diameter cylindrical side part, and a small-diameter cylindrical side part, is characterized in that: the inner side part of the large-diameter cylinder and the outer side part of the small-diameter cylinder are filled with subgrade filler, and the inner side of the small-diameter cylinder is filled with subgrade filler; the compressible function of the large cylindrical surface and the small cylindrical surface of the density bucket is realized through an annular corrugated part and has lateral restraint and vertical free compression functions.

[0007] Preferably, the materials of the large-diameter and small-diameter cylinders have a density of 2.2 g / cm3.

[0008] The present invention also discloses a method for detecting filling body parameters and controlling compaction quality for power performance matching, which is a compaction quality control method based on real-time detection of filler density during the vibration rolling process of a railway subgrade, and includes the following steps:

[0009] Step 1: Fabricate a compressible density bucket with dimensions suitable for on-site filling for different filler particle gradations, where the compressible density bucket consists of a base, a large-diameter cylindrical side part, a small-diameter cylindrical side part, filled with subgrade filler between the large-diameter cylindrical side and the small-diameter cylindrical side, filled with subgrade filler inside the small-diameter cylindrical side, and the compressible function of the density bucket is realized through an annular corrugated part and has lateral restraint and vertical free compression functions;

[0010] Step 2: Fill the density bucket with subgrade filler, and weigh the total weight M of the filler in the density bucket, the height H1 of the density bucket, the small diameter R1 of the density bucket, and the large diameter R2 of the density bucket;

[0011] Step 3: Arrange acceleration sensors or displacement sensors at the base or top position of the density bucket, denoted as A1, A2, U1, and U2.

[0012] Step 4: Calculate the density of the density bucket;

[0013] Step 5: Calculate the filler density during the vibration compaction process;

[0014] Step 6: Obtain the maximum dry density of the filler during the vibration compaction process through a heavy hammer compaction test ;

[0015] Step 7: Obtain the moisture content of the filler by drying the soil sample in an indoor oven ;

[0016] Step 8: Obtain the dynamic compaction coefficient through the dynamic density and the maximum dry density of the filler ;

[0017] Step 9: Repeat steps 4 - 8 above to obtain the time history curve of the dynamic compaction coefficient for different rolling passes;

[0018] Step 10: According to Section 6.3 of the "High-Speed Railway Design Code" and the embankment part below the subgrade bed in Section 6.4, it can be known that the compaction standards for the subgrade bed surface layer, the subgrade bed bottom layer, and the embankment below the subgrade bed are 97%, 95%, and 92% respectively;

[0019] Step 11: Compare the dynamic compaction coefficient obtained in Step 8 with the compaction standard required by the specification in Step 10, and monitor the change law of the compaction state of the filling material during the vibration compaction process in real time, avoiding under-compaction and over-compaction of the vibratory roller. Beneficial effects

[0020] (1) This method belongs to a non-destructive detection method for the compaction coefficient of filling materials during the vibration compaction process;

[0021] (2) This method proposes a control method for the compaction process of different types of filling materials, effectively avoiding over-compaction and under-compaction during the vibration compaction process;

[0022] (3) This method is a direct detection method for the compaction coefficient of filling materials during the vibration compaction process. Brief description of the drawings

[0023] Figure 1 The top view and front view of the compressible density bucket of the present invention;

[0024] Figure 2 Schematic diagram of the layout method of the acceleration / displacement sensor of the present invention;

[0025] Figure 3 Schematic diagram of the acceleration time history curves at the top and bottom of the density bucket of the present invention;

[0026] Figure 4 Schematic diagram of the time history curve of the displacement difference change between the top and bottom of the density bucket of the present invention, where (a) is the schematic diagram of the displacement time history curve at the top of the density bucket; (b) is the schematic diagram of the displacement time history curve at the bottom of the density bucket; (c) is the schematic diagram of the time history curve of the displacement difference change between the top and bottom of the density bucket;

[0027] Figure 5 Schematic diagram of the time history curve of the height change of the density bucket during the first pass of vibration rolling;

[0028] Figure 6 Schematic diagram of the time history curve of the density change of the filling material in the density bucket during the first pass of vibration rolling;

[0029] Figure 7 Schematic diagram of the time history curve of the dry density change of the filling material in the density bucket during the first pass of vibration rolling;

[0030] Figure 8 Schematic diagram of the time history curve of the dynamic compaction coefficient change of the filling material in the density bucket during the first pass of vibration rolling;

[0031] Figure 9 This is a schematic diagram of the variation law of the compaction coefficient of the present invention with the number of rolling passes. Specific embodiments

[0032] The present invention will be further described in detail below in conjunction with specific embodiments. The embodiments given are only for clarifying the present invention and not for limiting the scope of the present invention.

[0033] A method for detecting the parameters of a filling body and controlling the compaction quality with matching dynamic performance includes the following steps:

[0034] Step (1): Fabricate a compression density barrel with dimensions suitable for the on-site filling process for different filler particle gradations. The compressible density barrel consists of a base, a large-diameter cylindrical side part (material density is 2.2 g / cm 3 ), a small-diameter cylindrical side part (material density is 2.2 g / cm 3 ), the space between the large-diameter cylindrical side and the small-diameter cylindrical side is filled with subgrade filler, the inside of the small-diameter cylindrical side is filled with subgrade filler, and the compressible function of the density barrel is realized through an annular corrugated part and has lateral restraint and vertical free compression functions.

[0035] Step (2): Fill the density barrel with subgrade filler, and weigh the total weight M of the filler in the density barrel, the height H1 of the density barrel, the small diameter R1 of the density barrel, and the large diameter R2 of the density barrel.

[0036] The total weight M of the filler in the density barrel = 100 kg, the height H1 of the density barrel = 0.4 m, the small diameter R1 of the density barrel = 0.3 m, the large diameter R2 of the density barrel = 0.4 m,

[0037] Step (3): Refer to Appendix Figure 2 , arrange displacement sensors at the base position of the density barrel, and arrange acceleration sensors or displacement sensors respectively, denoted as A1, A2, U1, and U2.

[0038] Step (4): There are two ways to calculate the time history curve of the relative compression amount between the top and bottom surfaces of the density bucket. ① Analyze by collecting the acceleration time history curves of the top and bottom of the density bucket through a collector. Perform a second integral on the acceleration time history curves to obtain the displacement time history curves during the vibration compaction process. Obtain the time history curve of the relative compression amount between the top and bottom surfaces of the density bucket from the displacement peak values within 0.5 s of the top and bottom, denoted as h1. This method requires less space for installation and can directly calculate the density by ignoring the volume of the sensor. ② Monitor the direct displacement time history curves of the top and bottom of the density bucket through a collector, and then obtain the time history curve of the relative compression amount between the top and bottom surfaces of the density bucket from the displacement peak values within 0.5 s of the top and bottom, denoted as h1. However, the displacement sensor has a large volume, which affects the volume occupied by the filler in the density bucket. It is necessary to estimate the volume of the displacement sensor through the sand replacement method and then perform density calculation. See Attachment Figure 3 。

[0039] Step (5): Calculation method of the filler density during the vibration compaction process:

[0040] See Figure 4 As shown, (a) By monitoring the acceleration time history curves of the bottom and top of the density bucket during the vibration compaction process: ① The time history curve H of the density bucket height change a is the difference between the density bucket height H1 and the relative displacement time history curve h1 of the bottom and top of the density bucket obtained through frequency domain second integral. ② The initial density of the filler is the ratio of the filler mass M to the filler volume ( ). ③ The dynamic density during the vibration process is 。

[0041] (b) By monitoring the displacement time history curves of the bottom and top of the density bucket during the vibration compaction process: ① The time history curve H of the density bucket height change a is the difference between the density bucket height H1 and the relative displacement time history curve h1 of the bottom and top of the density bucket. ② Since the volume and mass of the density bucket occupied by the displacement sensor including the bottom fixed plate and the sensor part cannot be ignored, the overall volume of the displacement sensor is first obtained through the sand replacement method. The specific calculation steps are as follows: Given that the density of the standard sand is , place the displacement sensor into an empty bucket V with a known volume, pour the standard sand into the empty bucket in the form of free fall until the empty bucket is full, take out the displacement sensor, and record the remaining standard sand mass in the bucket as , then the volume V d of the sensor is . ③ The initial density of the filler is the ratio of the filler mass (M - ) to the filler volume ( - V dRatio. ④ During the vibration process, the dynamic density is . See Appendix Figure 5 as shown.

[0042] Taking the first pass of vibration compaction of a vibratory roller as an example:

[0043] The time-history curve of the height change of the density bucket during the first pass of vibration compaction indicates that the longitudinal displacement of the barrel wall of the compressible density bucket occurs during the vibration compaction process. Therefore, the packing material inside the bucket also undergoes longitudinal compression, and then the time-history curve of the compression amount of the packing material is obtained. The time-history curve of the density change of the packing material inside the density bucket during the first pass of vibration compaction represents the real-time density change curve of the packing material during the compaction process, and thus the purpose of monitoring the density of the packing material during the compaction process is achieved.

[0044] Step (6): Conduct 96 heavy compactions with different water contents under the condition of the same grading curve through indoor heavy compaction tests to obtain the maximum dry density of the packing material .

[0045] According to engineering experience, it is known that the maximum dry density of the packing material is 2.3 g / cm 3 .

[0046] Step (7): Obtain the water content of the packing material by drying the soil sample in an indoor oven .

[0047] According to engineering experience, it is known that the water content of the packing material is generally 4%.

[0048] Step (8): Obtain the dynamic compaction coefficient by comparing the dynamic density with the maximum dry density of the packing material ;

[0049] The time-history curve of the dry density change of the packing material inside the density bucket during the first pass of vibration compaction is the time-history curve of the dry density change of the packing material obtained by combining the water content, and then it is compared with the maximum dry density obtained from indoor tests to obtain the compaction coefficient.

[0050] The time-history curve of the dynamic compaction coefficient change of the packing material inside the density bucket during the first pass of vibration compaction is obtained by comparing the time-history curve of the dry density measured on-site with the maximum dry density, and is used to judge the compaction quality of the packing material.

[0051] Step (9): Repeat the above steps (4)-(8) to obtain the time-history curves of the dynamic compaction coefficients for different numbers of compaction passes.

[0052] The variation law of the compaction coefficient with the number of compaction passes is obtained by comparing the dry density results after each compaction. The purpose is to obtain the variation law of the compaction coefficient under different numbers of compaction passes. If the standard value is reached, the compaction can be stopped in time to achieve the purpose of dynamic monitoring.

[0053] Step (10): According to Section 6.3 and the subgrade below the bed section of the "Code for Design of High-Speed Railway", it can be known that the compaction standards for the surface layer of the bed, the bottom layer of the bed, and the subgrade below the bed are 97%, 95%, and 92% respectively.

[0054] According to the graph of the variation law of the compaction coefficient with the number of rolling passes, the compaction times corresponding to the compaction coefficients of 97%, 95%, and 92% are 19 times, 12 times, and 7 times respectively. Thus, the vibration compaction times are accurately obtained, avoiding over-compaction and under-compaction.

[0055] Step (11): Compare the dynamic compaction coefficient obtained in step (8) with the compaction standard required by the specification in step (9), and monitor the change law of the compaction state of the filling material during the vibration compaction process in real time, avoiding under-compaction and over-compaction of the vibratory roller.

[0056] The production method proposed by the present invention is simple to operate, highly feasible, and is a method for directly detecting the compaction coefficient with extremely high efficiency. The present invention completes the detection of compaction quality during the construction stage and adjusts the construction conditions in the areas with poor compaction states, avoiding over-compaction and under-compaction, greatly improving the quality inspection efficiency of high-speed railway subgrade construction, and having significant economic and social benefits.

[0057] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for dynamic performance matching of fill parameters and compaction quality control, characterized by: Step 1: Make compressible density barrels with sizes suitable for on-site filling process according to different filler particle gradations; Step 2: Fill the density barrel with roadbed filler, and weigh the total weight M of the filler in the density barrel, the height H1 of the density barrel, the small diameter R1 of the density barrel, and the large diameter R2 of the density barrel; Step 3: Arrange acceleration sensors or displacement sensors at the base and top of the density barrel, denoted as A1, A2 and U1, U2; Step 4: Calculate the density of the density bucket; Step 5: Calculation of filler density during vibration compaction; Step 6: Obtain the maximum dry density of the filler during vibration compaction by heavy hammer compaction test ; Step 7: Dry the soil sample in an indoor oven to obtain the moisture content of the filler ; Step 8: Dynamic Density Maximum dry density of filler Get the dynamic compaction coefficient ; Step 9: Repeat the above steps 4-8 to obtain the time history curve of the dynamic compaction coefficient with different rolling times; Step 10: According to Section 6.3 and Section 6.4 of the High-Speed ​​Railway Design Code for Embankments below the Subgrade, the compaction standards for the subgrade surface layer, subgrade bottom layer, and embankments below the subgrade are 97%, 95%, and 92%, respectively; Step 11: Compare the dynamic compaction coefficient obtained in step 8 According to the compaction standard required by the specification in step 10, the changing law of the compaction state of the filler during the vibration compaction process is monitored in real time to avoid under-pressure and over-pressure of the vibratory roller; The compressible density barrel comprises a base, a large diameter cylindrical side portion, and a small diameter cylindrical side portion; the inner side portion of the large diameter cylinder and the outer side portion of the small diameter cylinder are filled with roadbed filler, and the inner side of the small diameter cylinder is filled with roadbed filler; the compressible function of the large cylindrical surface and the small cylindrical surface of the density barrel is realized through the annular corrugated portion and has lateral constraint and vertical free compression functions.

2. The method for detecting parameters of compacted objects and controlling compaction quality with dynamic performance matching according to claim 1, characterized in that: The compressible density barrel consists of a base, a large-diameter cylindrical side portion, and a small-diameter cylindrical side portion. The space between the large-diameter cylindrical side portion and the small-diameter cylindrical side portion is filled with a roadbed filler, and the interior of the small-diameter cylindrical side portion is filled with a roadbed filler.

3. The method for detecting parameters of compacted objects and controlling compaction quality with dynamic performance matching according to claim 1, characterized in that: There are two ways to calculate the relative compression time-history curve between the top and bottom of the density barrel: ① Use a data collector to monitor the acceleration time-history curve of the top and bottom of the density barrel for analysis, perform quadratic integration on the acceleration time-history curve to obtain the displacement time-history curve during the vibration rolling process, and obtain the relative compression time-history curve between the top and bottom of the density barrel by taking the displacement peak values ​​within 0.5s of the top and bottom of the barrel, which is recorded as h1; ② Use a data collector to monitor the displacement time-history curve directly between the top and bottom of the density barrel, and then obtain the relative compression time-history curve between the top and bottom of the density barrel by taking the displacement peak values ​​within 0.5s of the top and bottom of the barrel, which is recorded as h1.

4. The method for detecting parameters of compacted objects and controlling compaction quality with dynamic performance matching according to claim 3 is characterized by: The method for calculating the density of the packing during vibration compaction includes the following steps: (a) By monitoring the acceleration time history curves of the bottom and top of the density barrel during vibration compaction: ① The time history curve of the density barrel height change H a is the difference between the density bucket height H1 and the relative displacement time history curve h1 between the bottom and top of the density bucket obtained by quadratic integration in the frequency domain; ② The initial density of the filler is is the packing mass M and the packing volume The ratio of ③ the dynamic density during vibration is = ; (b) By monitoring the displacement time history curve of the bottom and top of the density barrel during vibration compaction: ① Density barrel height change time history curve H a It is the difference between the density barrel height H1 and the relative displacement time history curve h1 between the bottom and top of the density barrel. ② Since the displacement sensor includes the bottom fixed plate and the sensor part, the volume and mass of the density barrel It cannot be ignored, so the overall volume of the displacement sensor is first obtained by the sand filling method. The specific calculation steps are as follows: The density of the standard sand is known to be , put the displacement sensor into an empty bucket V of known volume, pour the standard sand into the empty bucket by free fall until the bucket is full, take out the displacement sensor, and record the remaining standard sand mass in the bucket as , then the volume of the sensor V d for ; ③The initial density of the filler is is the filler mass M- With filler volume -V d ratio; ④ The dynamic density during vibration is = .

5. A compaction quality control method based on real-time detection of filler density during railway roadbed vibration rolling, characterized by: The method adopts a dynamic performance matching filling body parameter detection and compaction quality control method as described in any one of claims 1-4.

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