阅读说明：本技术 一种基于波速理论的路基压实特性在线监测方法 (Roadbed compaction characteristic on-line monitoring method based on wave velocity theory ) 是由 王雪菲 陈思德 李家乐 于 2021-08-30 设计创作，主要内容包括：本发明一种基于波速理论的路基压实特性在线监测方法,该方法包括下述内容：对待检测路段点位采用环刀法取样测量压实土体密度；测量待检测路段点位的横波、纵波和瑞利波波速；利用三种波速、压实土体密度与介质材料特性的相关关系,计算压实土体特性的相关参数,压实土体特性的相关参数包括泊松比、弹性模量、剪切模量,检测路基压实质量。本申请省去了实验室内的复杂试验过程,在现场即可完成实时监测,高效快捷,本发明能将测量结果上传数据管理系统,对路基压实特性进行在线监测。(The invention relates to a roadbed compaction characteristic on-line monitoring method based on a wave velocity theory, which comprises the following steps: sampling and measuring the density of the compacted soil body at the point position of the road section to be detected by adopting a cutting ring method; measuring the wave speed of transverse waves, longitudinal waves and Rayleigh waves of point positions of a road section to be detected; and calculating relevant parameters of the characteristics of the compacted soil body by utilizing the correlation among the three wave velocities, the density of the compacted soil body and the characteristics of the medium material, wherein the relevant parameters of the characteristics of the compacted soil body comprise Poisson's ratio, elastic modulus and shear modulus, and detecting the compaction quality of the roadbed. According to the method, a complex test process in a laboratory is omitted, real-time monitoring can be completed on site, the method is efficient and rapid, and the method can upload the measurement result to a data management system to perform online monitoring on the compaction characteristics of the roadbed.)

1. A roadbed compaction characteristic on-line monitoring method based on a wave velocity theory comprises the following steps:

1) sampling and measuring the density of the compacted soil body at the point position of the road section to be detected by adopting a cutting ring method;

2) measuring the wave speed of transverse waves, longitudinal waves and Rayleigh waves of point positions of a road section to be detected;

3) and calculating relevant parameters of the characteristics of the compacted soil body by utilizing the correlation among the three wave velocities, the density of the compacted soil body and the characteristics of the medium material, wherein the relevant parameters of the characteristics of the compacted soil body comprise Poisson's ratio, elastic modulus and shear modulus, and detecting the compaction quality of the roadbed.

2. The on-line monitoring method of claim 1, wherein the correlation between the three wave velocities and the compacted soil density and the characteristics of the soil medium material is as follows:

wherein, V_P-longitudinal wave velocity, m/s; v_S-transverse wave velocity, m/s; v_R-rayleigh wave velocity, m/s; rho-density of wave propagation medium, kg/m³(ii) a E-modulus of elasticity, kPa; g-shear modulus, kPa; mu-Poisson's ratio.

3. The on-line monitoring method according to claim 2,

in the measuring process of the transverse wave velocity and the longitudinal wave velocity, the density of the compacted soil body needs to be determined, and the specific process is as follows: taking soil at the same depth by using a cutting ring, wherein the volume V of the cutting ring is known, and the compacted soil density can be obtained by only measuring the mass m1 of the cutting ring and the mass m2 of the soil mass added by the cutting ring

For the measurement of the Rayleigh wave velocity, a transient excitation mode is adopted, so that the shot falls down from a specified height, and vibration is generated in a point area;

carrying the measured transverse wave velocity and Rayleigh wave velocity into formula (3) to obtain the Poisson ratio of the compacted soil, substituting the Poisson ratio of the compacted soil, the measured density of the compacted soil and the measured longitudinal wave velocity into formula (1) to obtain the elastic modulus of the compacted soil, and substituting the density of the soil into formula (2) to obtain the shear modulus G of the compacted soil; and finally, uploading the measured data to a data management system, completing the visual processing of the characteristics of the compacted roadbed material, further reflecting the compaction characteristic information of the construction full section, monitoring whether the roadbed compaction quality meets the requirements according to the construction specifications, storing the data to a big data platform, guiding the construction process, and providing a basis for a quality tracing system.

4. The on-line monitoring method according to claim 2, wherein the specific process of calculating the relevant parameters of the compacted soil characteristics is:

measuring the wave velocity of the transverse wave and the wave velocity of the longitudinal wave, and simultaneously measuring the wave velocity of the transverse wave and the wave velocity of the longitudinal waveAndthe calculated poisson ratio is mu 1;

measuring the wave velocity of the transverse wave and the wave velocity of the Rayleigh wave of the surface wave, calculating the Poisson ratio to be mu 2 according to the formula (3),

if μ 1<Mu 2, the Poisson ratio of the current point position compacted soil body is mu 2, the mu 2 is directly substituted into the formula (1) to calculate the elastic modulus E, and then the formula is usedCalculating a shear modulus G;

if the mu 1 is more than the mu 2, the Poisson ratio of the current point compaction soil body is mu 1, the mu 1 is taken into the formula (1) to calculate the elastic modulus E, and the formula (2) is replaced to calculate the shear modulus G.

5. The on-line monitoring method according to claim 1, wherein the specific process of the monitoring method is as follows:

in the actual compaction construction process, the subsequent compaction characteristic parameters are monitored in real time under the condition that the compacted soil parameters meet the engineering requirements; the whole roadbed project is divided into a plurality of sections at equal intervals during sampling, the position of each section is determined by a GPS system, each section is marked as a point position, the distance of each section is set to be 15-20 m, each compaction of each section is monitored once, a cutting ring method is used for sampling at any position in the section area, the middle area of the section of the road is taken for testing three wave speeds, and the testing result represents the compaction characteristic of the section of the distance;

1) sampling in a point position by adopting a cutting ring method after the rolling of the road roller meets the engineering requirement according to the actual engineering, and calculating the density rho of the compacted soil body at the current point position;

2) the method comprises the following steps of connecting relevant equipment for measuring body wave and surface wave velocity, wherein in a surface wave collection test, the used equipment comprises a processing terminal, a dynamic data acquisition instrument, a plurality of acceleration sensors and a shot, wherein the acceleration sensors are distributed in a road section to be measured at equal intervals along the same straight line, the acceleration sensors are all located in the action range of shot vibration, and each acceleration sensor is a measuring point; all the acceleration sensors are connected with a dynamic data acquisition instrument, the dynamic data acquisition instrument is connected with a processing terminal, a stable waveform is obtained through adjustment, after the stable waveform is acquired, a shot is dropped from a height to generate vibration, each acceleration sensor corresponds to one channel, and the waveform can be observed to obviously change through each channel;

measuring the wave velocity of transverse waves and longitudinal waves in body waves by adopting a bending element mode, wherein the measured wave velocity is regarded as the wave velocity of the transverse waves and the longitudinal waves of a body wave measuring point, and the transverse waves and the longitudinal waves in the body waves are collected to obtain the middle position of any two adjacent acceleration sensors when surface waves are collected in the field test process; inserting probes into the roadbed at the same depth, starting a function generator, generating sine wave electric signals, transmitting the sine wave electric signals to an excitation element through a charge amplifier, transmitting the sine wave electric signals to a soil body, receiving the relevant electric signals by a receiving element, and displaying clear and stable waveforms by an oscilloscope; respectively measuring transverse waves and longitudinal waves according to different sine wave electric signals generated by the function generator;

3) carrying out three repeated tests on each point location, and taking the average value of the repeated tests as the measurement result of the current point location; the whole engineering field is uniformly divided into N sections along the length direction, each section of single compaction area is collected once, the whole engineering field is subjected to multi-point collection, the whole engineering field is uniformly divided so that collected collection points of the whole engineering field are distributed over the whole engineering, the problem that the collection points are excessively concentrated in a certain area is avoided, the whole engineering can be covered as much as possible, the integral collection quantity is N, random collection of the field is required after measurement is completed according to a sectional mode, and the quantity of the collection points subjected to random sampling is not less than 10% of the integral collection quantity;

4) calculating wave velocity, wherein the time difference from the excitation element to the receiving element is t for the transverse wave and the longitudinal wave in the body wave_s、t_pThe distance between the exciting element and the receiving element is L1, the two elements reach the same depth, and the wave speed is V according to the change of the function generator to be transverse wave or longitudinal wave_S＝L1/t_s、V_P＝L1/t_p(unit: m/s);

calculating the wave velocity of the Rayleigh wave, respectively recording the arrival time tn of the acceleration peak values of a plurality of acceleration sensors, and if the number of the acceleration sensors is n, the linear distance between two adjacent acceleration sensors is L2, the distance between the first acceleration sensor and the last acceleration sensor is (n-1) L2, and the wave velocity of the Rayleigh wave is calculated

5) Substituting the three wave velocities obtained in the step 4) and the compacted soil density of the corresponding point location obtained in the step 1) into the correlation relationship in the claim 2, obtaining the elasticity modulus, the shear modulus and the Poisson ratio of the compacted soil at the current point location and the compaction pass, and obtaining the compaction characteristics of the whole roadbed project through the test of different compaction passes at multiple points.

6. The on-line monitoring method of claim 5, wherein a Beidou positioning system is combined to transmit compaction characteristic data of the whole roadbed project to a data management system in real time, visual processing of characteristics of the compacted roadbed material is completed, further compaction characteristic information of a full section of construction is reflected, body wave measurement is in a depth direction, the driving depth of each construction is kept the same, surface waves are in a surface direction, multi-angle detection can be performed, after fillers are paved, compaction is performed layer by layer, monitoring is performed in each lamination process, timely monitoring of the whole section is achieved, whether roadbed compaction quality meets requirements or not is monitored according to construction specifications, data are stored to a large data platform, construction progress is guided, and a basis is provided for a quality tracing system.

7. The on-line monitoring method according to claim 5, wherein the straight-line distance between two adjacent acceleration sensors is L2 is 1-2 m; the mass of the shot is 5kg, the shot falls from a specified height of 1.2-1.8 m, and the horizontal distance between the shot and a nearest measuring point is 0.5 m; the distance L1 between the excitation element and the receiving element is 8-12 cm.

Technical Field

The invention relates to a roadbed compaction characteristic on-line monitoring method based on a wave velocity theory.

Background

The quality of the filler and the rolling compaction is the main factor for determining the engineering quality of the roadbed, and the compaction characteristic of the roadbed after rolling compaction becomes the key of the engineering quality on the premise of determining the filler. In the roadbed compaction process, the compaction characteristics of the roadbed need to be monitored, whether the compaction quality meets the requirements or not is detected according to the construction specification requirements, and the problems of insufficient compaction and excessive compaction are avoided.

The compaction quality accessible compactness of road bed reflects, the compaction quality is reflected through measuring dry density mostly at present, consequently use the cutting ring method and irritate the sand method and carry out the on-the-spot detection of getting on the road bed after the compaction, the sample need be brought back the laboratory and carry out a large amount of density measurations, the unable very first time of measuring result reachs, have the time delay, it is difficult to avoid can appearing packing not tight in the transportation of soil sample, the condition that moisture scatters and disappears, influence the accuracy nature of result, and use and irritate the sand method sampling in-process and need excavate the road bed, destroy the wholeness of road bed, cause the harm that can not neglected.

The Chinese patent with the application number of 202010827216.0 discloses a method for detecting the compaction quality of coarse-particle soil roadbed fillers based on shear wave velocity, in order to find the relation between roadbed compaction degree and shear wave velocity, an indoor compaction test needs to be carried out, and a roadbed filler test soil sample with the same gradation and the same water content as the roadbed fillers used on the site needs to be prepared; the shear wave velocity test of the roadbed filler test soil samples under different compactnesses is carried out, the shear wave velocity values of the roadbed filler test soil samples corresponding to the different compactnesses are obtained, different soil samples need to be prepared for indoor tests of different roadbed materials, the early-stage preparation work is long in time consumption, and the method has no universality on different types of fillers.

Therefore, a new method for monitoring the compaction characteristics of the roadbed needs to be developed, so that the compaction quality of the roadbed can be accurately, safely, quickly and quickly monitored, and the damage to the roadbed in the monitoring process is reduced.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to solve the technical problem of providing the roadbed compaction characteristic on-line monitoring method based on the wave velocity theory, wherein the monitoring method detects the compaction characteristic of the roadbed according to the relation among the transverse wave, the longitudinal wave, the Rayleigh wave and the relevant parameters of the compaction soil body characteristic by measuring the wave velocities of the transverse wave, the longitudinal wave and the Rayleigh wave of the compaction soil body, and further reflects the compaction characteristic of the detected road section. According to the method, a complex test process in a laboratory is omitted, real-time monitoring can be completed on site, the method is efficient and rapid, and the method can upload the measurement result to a data management system to perform online monitoring on the compaction characteristics of the roadbed.

The technical scheme for solving the technical problems is as follows:

a roadbed compaction characteristic on-line monitoring method based on a wave velocity theory comprises the following steps:

1) sampling and measuring the density of the compacted soil body at the point position of the road section to be detected by adopting a cutting ring method;

2) measuring the wave speed of transverse waves, longitudinal waves and Rayleigh waves of point positions of a road section to be detected;

3) and calculating relevant parameters of the characteristics of the compacted soil body by utilizing the correlation among the three wave velocities, the density of the compacted soil body and the characteristics of the medium material, wherein the relevant parameters of the characteristics of the compacted soil body comprise Poisson's ratio, elastic modulus and shear modulus, and detecting the compaction quality of the roadbed.

The correlation relations between the three wave velocities, the compacted soil density and the soil medium material characteristics are as follows:

wherein, V_P-longitudinal wave velocity, m/s; v_S-transverse wave velocity, m/s; v_R-rayleigh wave velocity, m/s; rho-density of wave propagation medium, kg/m³(ii) a E-modulus of elasticity, kPa; g-shear modulus, kPa; mu-Poisson's ratio.

In the measuring process of the transverse wave velocity and the longitudinal wave velocity, the density of the compacted soil body needs to be determined, and the specific process is as follows: taking soil at the same depth by using a cutting ring, wherein the volume V of the cutting ring is known, and the compacted soil density can be obtained by only measuring the mass m1 of the cutting ring and the mass m2 of the soil mass added by the cutting ring

For the measurement of the Rayleigh wave velocity, a transient excitation mode is adopted, so that the shot falls down from a specified height, and vibration is generated in a point area;

carrying the measured transverse wave velocity and Rayleigh wave velocity into formula (3) to obtain the Poisson ratio of the compacted soil, substituting the Poisson ratio of the compacted soil, the measured density of the compacted soil and the measured longitudinal wave velocity into formula (1) to obtain the elastic modulus of the compacted soil, and substituting the density of the soil into formula (2) to obtain the shear modulus G of the compacted soil; and finally, uploading the measured data to a data management system, completing the visual processing of the characteristics of the compacted roadbed material, further reflecting the compaction characteristic information of the construction full section, monitoring whether the roadbed compaction quality meets the requirements according to the construction specifications, storing the data to a big data platform, guiding the construction process, and providing a basis for a quality tracing system.

The specific process for calculating the relevant parameters of the compacted soil characteristics comprises the following steps:

measuring the wave velocity of the transverse wave and the wave velocity of the longitudinal wave, and simultaneously measuring the wave velocity of the transverse wave and the wave velocity of the longitudinal wave The calculated poisson ratio is mu 1;

measuring the wave velocity of the transverse wave and the wave velocity of the Rayleigh wave of the surface wave, calculating the Poisson ratio to be mu 2 according to the formula (3),

if μ 1<Mu 2, the Poisson ratio of the current point position compacted soil body is mu 2, the mu 2 is directly substituted into the formula (1) to calculate the elastic modulus E, and then the formula is usedCalculating a shear modulus G;

if the mu 1 is more than the mu 2, the Poisson ratio of the current point compaction soil body is mu 1, the mu 1 is taken into the formula (1) to calculate the elastic modulus E, and the formula (2) is replaced to calculate the shear modulus G.

The invention relates to a roadbed compaction characteristic on-line monitoring method based on a wave velocity theory, which comprises the following specific processes:

in the actual compaction construction process, the subsequent compaction characteristic parameters are monitored in real time under the condition that the compacted soil parameters meet the engineering requirements; the whole roadbed project is divided into a plurality of sections at equal intervals during sampling, the position of each section is determined by a GPS system, each section is marked as a point position, the distance of each section is set to be 15-20 m, each compaction of each section is monitored once, a cutting ring method is used for sampling at any position in the section area, the middle area of the section of the road is taken for testing three wave speeds, and the testing result represents the compaction characteristic of the section of the distance;

1) sampling in a point position by adopting a cutting ring method after the rolling of the road roller meets the engineering requirement according to the actual engineering, and calculating the density rho of the compacted soil body at the current point position;

2) the method comprises the following steps of connecting relevant equipment for measuring body wave and surface wave velocity, wherein in a surface wave collection test, the used equipment comprises a processing terminal, a dynamic data acquisition instrument, a plurality of acceleration sensors and a shot, wherein the acceleration sensors are distributed in a road section to be measured at equal intervals along the same straight line, the acceleration sensors are all located in the action range of shot vibration, and each acceleration sensor is a measuring point; all the acceleration sensors are connected with a dynamic data acquisition instrument, the dynamic data acquisition instrument is connected with a processing terminal, a stable waveform is obtained through adjustment, after the stable waveform is acquired, a shot is dropped from a height to generate vibration, each acceleration sensor corresponds to one channel, and the waveform can be observed to obviously change through each channel;

measuring the wave velocity of transverse waves and longitudinal waves in body waves by adopting a bending element mode, wherein the measured wave velocity is regarded as the wave velocity of the transverse waves and the longitudinal waves of a body wave measuring point, and the transverse waves and the longitudinal waves in the body waves are collected to obtain the middle position of any two adjacent acceleration sensors when surface waves are collected in the field test process; inserting probes into the roadbed at the same depth, starting a function generator, generating sine wave electric signals, transmitting the sine wave electric signals to an excitation element through a charge amplifier, transmitting the sine wave electric signals to a soil body, receiving the relevant electric signals by a receiving element, and displaying clear and stable waveforms by an oscilloscope; respectively measuring transverse waves and longitudinal waves according to different sine wave electric signals generated by the function generator;

3) carrying out three repeated tests on each point location, and taking the average value of the repeated tests as the measurement result of the current point location; the whole engineering field is uniformly divided into N sections along the length direction, each section of single compaction area is collected once, the whole engineering field is subjected to multi-point collection, the whole engineering field is uniformly divided so that collected collection points of the whole engineering field are distributed over the whole engineering, the problem that the collection points are excessively concentrated in a certain area is avoided, the whole engineering can be covered as much as possible, the integral collection quantity is N, random collection of the field is required after measurement is completed according to a sectional mode, and the quantity of the collection points subjected to random sampling is not less than 10% of the integral collection quantity;

4) calculating wave velocity, wherein the time difference from the excitation element to the receiving element is t for the transverse wave and the longitudinal wave in the body wave_s、t_pThe distance between the exciting element and the receiving element is L1, the two elements reach the same depth, and the wave speed is V according to the change of the function generator to be transverse wave or longitudinal wave_S＝L1/t_s、V_P＝L1/t_p(unit: m/s);

calculating the wave velocity of the Rayleigh wave, respectively recording the arrival time tn of the acceleration peak values of a plurality of acceleration sensors, and if the number of the acceleration sensors is n, the linear distance between two adjacent acceleration sensors is L2, the distance between the first acceleration sensor and the last acceleration sensor is (n-1) L2, and the wave velocity of the Rayleigh wave is calculated

5) Substituting the three wave velocities obtained in the step 4) and the compacted soil density of the corresponding point location obtained in the step 1) into the correlation relationship in the claim 2 to obtain the elasticity modulus, the shear modulus and the Poisson ratio of the compacted soil at the current point location and the compaction pass,

and the compaction characteristics of the whole roadbed project can be obtained through the test of multipoint positions and different compaction passes.

Compared with the prior art, the invention has the beneficial effects that:

the monitoring method can directly measure the density of the compacted soil by using a cutting ring method, is used for directly calculating the compaction characteristic without indirectly calculating the dry density, does not need a large amount of sampling and measurement compared with the prior method for measuring the compaction characteristic by depending on the dry density, only needs to adopt a simple cutting ring to take the soil and measure the density of the compacted soil, reduces the sampling and a large amount of laboratory measuring work, saves a large amount of time and enables the whole measuring process to be fast and convenient. Compared with a nuclear densitometer method, the method for detecting the roadbed compaction characteristics by using the wave velocity theory has the advantages of reduced technical requirements, safer operation and wider application range. Meanwhile, the damage of the compacted soil body caused by the excavation of holes in the sampling and measuring processes is reduced.

The invention combines three wave velocities, soil is taken by the cutting ring at the same depth in the process of measuring body waves, the volume V of the cutting ring is known, and the compacted soil density can be obtained by measuring the mass m1 of the cutting ring and the mass m2 of the soil mass added by the cutting ringFor the measurement of Rayleigh wave velocity, a transient excitation method is adopted, so that the shot can fall from a specified height to generate vibration, the instrument is simple and convenient, and the operation is simple; taking the measured shear wave velocity and Rayleigh wave velocity into the three wave velocities according to the relationship between the three wave velocities and the relevant parameters of the compaction characteristics such as Poisson ratio, elastic modulus, shear modulus and the likeThe Poisson's ratio of the compacted soil can be obtained, and the Poisson's ratio, the measured soil density and the measured longitudinal wave velocity are substituted into a formulaObtaining the elastic modulus of the compacted soil body and substituting the soil body density into the formulaThe shear modulus G of the compacted soil body can be obtained; and finally, uploading the measurement to a data management system, completing the visualization processing of the characteristics of the compacted roadbed material, further reflecting the compaction characteristic information of the construction full section, and monitoring the roadbed compaction according to the construction specificationsAnd if the quality meets the requirements, storing the data to a big data platform to guide the construction process and provide a basis for a quality tracing system.

The monitoring method of the invention avoids the defects of complicated monitoring process and large data volume caused by the fact that the functional relation between the compaction degree and the shear wave velocity is directly searched in the prior art that the shear wave velocity is adopted to monitor the compaction degree of the soil body, the indoor compaction test determination result needs to be matched, and the filler with the same field condition needs to be prepared and compacted. The method directly utilizes the relational expression of the three wave velocities and the compaction characteristic related parameters of the used compacted soil body, can directly obtain the compaction characteristic related parameters of the current point position on the premise of knowing the three wave velocities and the density, and has high accuracy. In the roadbed compaction characteristic monitoring process, the method greatly reduces the workload, and avoids a large amount of excavation sampling and measurement of indoor test parameters; the detection difficulty is reduced, the detection instrument is light as much as possible, the carrying is convenient, the operation is simple, and the detection process is high-speed and rapid; combining a plurality of methods, comparing with each other, selecting the optimal Poisson ratio, measuring the transverse wave velocity and the longitudinal wave velocity, obtaining the Poisson ratio according to the relational expression, measuring the surface wave Rayleigh wave velocity and the transverse wave velocity, and obtaining the Poisson ratio according to the relational expression. Both methods can calculate the Poisson's ratio, which is obviously in positive correlation with the water content and the porosity ratio and in negative correlation with the wet density. The higher the moisture content, the larger the void ratio, the lower the wet density, and the larger the poisson's ratio. The larger value of the calculated Poisson ratio of the two methods is selected, so that the construction safety can be relatively ensured. Damage to the roadbed is reduced in the detection process, and the integrity of the roadbed is ensured; the detection result is rapidly obtained, the construction continuity is guaranteed, a foundation is laid for the next construction, the construction road sections of different types of fillers can be monitored by the method, complex laboratory tests are not required to be combined, required parameters can be rapidly obtained, the timeliness of the detection result is guaranteed, the detection result is transmitted to a data management system in real time, visualization processing is realized, and the compaction characteristics of the construction full section can be reflected.

Drawings

FIG. 1: the invention discloses a flow schematic diagram of a roadbed compaction characteristic on-line monitoring method based on a wave velocity theory.

FIG. 2: the invention discloses a wave velocity processing process schematic diagram in a roadbed compaction characteristic on-line monitoring method based on a wave velocity theory.

FIG. 3: the invention relates to a wave velocity theory-based roadbed compaction characteristic on-line monitoring method, which is characterized in that a body wave transverse wave and longitudinal wave velocity acquisition device is connected with a schematic diagram.

FIG. 4: the invention relates to a schematic diagram of the installation of surface wave Rayleigh wave velocity acquisition equipment in a roadbed compaction characteristic on-line monitoring method based on a wave velocity theory.

Detailed Description

The invention provides an online monitoring method for roadbed compaction characteristics based on a wave velocity theory, and provides an accurate, safe, high-speed and rapid method for monitoring roadbed compaction quality in a roadbed construction process.

The wave velocity theory in the present application means that the propagation velocity of a wave is related to the characteristics of the medium.

The method comprises the steps of solving compaction characteristic parameters of a roadbed soil body by utilizing a wave velocity theory, detecting the roadbed compaction quality, measuring various wave velocities by utilizing the correlation of the wave velocities of transverse waves, longitudinal waves and Rayleigh waves and the characteristics of a medium material, simply sampling and measuring the density of the compacted soil body by adopting a ring cutter method, calculating the correlation parameters of the Poisson ratio, the elastic modulus and the shear modulus of the compacted soil body by utilizing a corresponding relational expression, and detecting the roadbed compaction quality. The compaction characteristics of the roadbed are reflected by the elastic modulus, the shear modulus and the Poisson ratio of a compacted soil body, and the on-line monitoring is realized by transmitting a point measurement result to a data management system to perform visual processing on the construction full-section compaction characteristic information. The propagation speed of the wave is influenced by the medium characteristics, the material characteristics of roadbed soil can change during rolling, a series of material characteristic parameters of Poisson's ratio, shear modulus and elastic modulus of the soil body after rolling construction are obtained through measuring the density of the compacted soil body, the propagation speed of transverse waves and longitudinal waves in the compacted soil body and the propagation speed of Rayleigh waves on the surface of the soil body, and the correlation between the wave speed and the medium characteristics, so that the quality of the compacted construction is reflected in real time.

In the wave velocity measuring process, a transient method is adopted for the excitation of vibration, so that the operation is simpler and more convenient. The method of the bending element is adopted for measuring the wave velocity of the transverse wave and the longitudinal wave in the body wave, the probe is inserted into the roadbed at the same depth, the function generator is started, sine wave electric signals are generated and transmitted to the excitation element through the charge amplifier, the sine wave electric signals are transmitted to the excitation element through the compacted soil body, the relevant electric signals are received by the receiving element, and the corresponding wave velocity can be obtained through the amplification and data processing of the electric signals; for the measurement of the wave speed of the surface wave Rayleigh wave, a heavy object is dropped on the compacted soil to generate transient vibration, an acceleration sensor collects an electric signal to obtain the wave speed of the corresponding surface wave Rayleigh wave, the wave speed of the surface wave Rayleigh wave is directly measured on site, the wave speed of the surface wave Rayleigh wave and the wave speed of the transverse wave are used to be brought into a correlation relationship, the Poisson ratio of the compacted soil can be obtained in real time, and the compaction characteristic of the compacted soil is further obtained. The results of the three wave velocity measurements are combined, and the compaction characteristic parameters of the whole roadbed soil body can be obtained.

As shown in figure 1, the method mainly comprises three wave velocity data acquisition and cutting ring soil borrowing to measure the density of the compacted soil body, and utilizes the relational expressions among the density of the compacted soil body, the transverse wave velocity, the longitudinal wave velocity, the surface wave Rayleigh wave velocity, the Poisson ratio of the characteristics of the compacted soil body, the shear modulus and the elastic modulus to solve the characteristic parameters of the compacted soil body, obtain the compaction quality of the roadbed, perform data transmission management, perform visualization processing on the compaction information of the full section, and determine the next working content according to the construction specifications.

For the wave velocity acquisition, as shown in fig. 2, a test site is selected, and the wave velocity acquisition equipment and a computer are connected to debug the equipment. After the preparation work is finished, exciting the test field, wherein the excitation modes of different waves are different, and the wave speeds of transverse waves and longitudinal waves are received by a receiving element, amplified by a charge amplifier and displayed on an oscilloscope; the surface wave can acquire related electric signals through the acceleration sensor, and the wave processing is carried out in electric signal processing software to calculate the related wave velocity.

In the actual compaction construction process, the invention can start to monitor the subsequent compaction characteristic parameters in real time under the condition that the compacted soil parameters meet certain engineering requirements.

1. According to the actual engineering, after the road roller rolls for a certain degree (can roll for a plurality of times), a cutting ring method is adopted for sampling, and the density rho of the compacted soil body is calculated. The whole roadbed project is equally divided into a plurality of sections during sampling, the position of each section is determined by a GPS system, generally, the distance of each section can be set to be 15m-20m, each section is monitored once, sampling is carried out at any position in the section area by a cutting ring method, three wave speeds are tested in the middle area of the section, and the test result represents the compaction characteristic of the distance.

2. Connecting relevant equipment for measuring the wave speed of the body wave and the surface wave, switching on a power supply, debugging the equipment, wherein in a body wave collection test, the used equipment comprises a notebook computer, an oscilloscope, a charge amplifier, a function generator, an excitation element and a receiving element, wherein the excitation element and the receiving element are deep into a certain section of road section, the excitation element and the receiving element are both connected with the charge amplifier, the output of the function generator is connected with the charge amplifier, the charge amplifier is connected with the oscilloscope, and the oscilloscope is connected with the notebook computer; the charge amplifier is used for amplifying charges to make waveforms more obvious; the function generator is used for generating certain specific periodic time function waveform signals;

the function generator generates sine wave electric signals, the sine wave electric signals are processed by the charge amplifier and transmitted to the excitation element, the sine wave electric signals are transmitted through the soil body, the receiving element can receive related electric signals, and the oscilloscope can display clear and stable waveforms; according to the sine wave electric signals generated by the function generator, the transverse wave and the longitudinal wave can be measured respectively.

In the surface wave collection test, the used equipment comprises a notebook computer, a dynamic data acquisition instrument, a plurality of acceleration sensors and a shot, wherein the acceleration sensors are equidistantly distributed in a section to be tested along the same straight line, the acceleration sensors are all positioned in the action range of shot vibration, each acceleration sensor is a measuring point, and the number of the measuring points is related to the action range of the falling of the shot; all acceleration sensors are connected with a dynamic data acquisition instrument, the dynamic data acquisition instrument is connected with a notebook computer (processing terminal), a stable waveform is obtained through adjustment, after the stable waveform is acquired, a shot is allowed to fall from a certain height to generate vibration, and the waveform can be observed to obviously change through each channel (one channel is calculated by each acceleration sensor). The computers used in the bulk wave and surface wave collection tests may be the same.

A DHDAS dynamic signal acquisition and analysis system matched with the dynamic data acquisition instrument is loaded in the processing terminal.

3. The method comprises the steps of collecting Rayleigh waves of a surface wave, wherein the surface wave speed is measured at a distance L2 (usually 1-2 m), placing a plurality of acceleration sensors on the surface of a compacted soil body according to a specified distance, dropping a 5kg shot from a specified height (about 1.5 m), setting the horizontal distance from a first measuring point 1 to be 0.5m, setting the horizontal distance L2 between adjacent measuring points to be 1-2m, and setting three measuring points on the same straight line.

4. For measuring the wave velocity of transverse waves and longitudinal waves in body waves, a bending element method is adopted, the distance between an excitation element and a receiving element is small, the measured wave velocity can be regarded as the wave velocity of the transverse waves and the longitudinal waves of a body wave measuring point, in the field test process, the transverse wave and the longitudinal wave in the body wave are collected, the middle position of two acceleration sensors is acquired when the surface wave is collected, in the embodiment, three acceleration sensors are arranged in the surface wave collection test, so that the measuring point position of the body wave collection test can be the middle position between any two adjacent acceleration sensors, the required function exciters are started to generate sine wave electric signals, the sine wave electric signals are transmitted to the excitation element through the charge amplifier, the sine wave electric signals are transmitted to the excitation element through the soil body, the receiving element receives related electric signals, the sine wave electric signals can be clearly displayed on the oscilloscope after being amplified by the charge amplifier, and the waveform is stored through the computer. The whole engineering field is equally divided into a plurality of sections along the length direction, each section of single-channel compacted area is acquired once, the whole engineering field is subjected to multi-point acquisition, the acquired acquisition points are distributed over the whole engineering field due to the fact that the whole engineering field is equally divided, the problem that the acquisition points are excessively concentrated in a certain area is avoided, the whole engineering field can cover the whole engineering field as much as possible, the whole engineering field refers to the whole roadbed engineering and is divided into N sections, therefore, the whole acquisition amount is N, random acquisition of the field is needed after measurement is completed in a sectional mode, the result is prevented from being accidentally enabled to be more convinciting, and the number of the acquisition points sampled randomly is not less than 10% of the whole acquisition amount.

Calculating wave velocity, wherein for the transverse wave and the longitudinal wave in the body wave, the time difference from the excitation element to the receiving element is t_s、t_pThe distance between the exciting element and the receiving element is L1, the two elements reach the same depth, and the wave speed is V according to the change of the function generator to be transverse wave or longitudinal wave_S＝L1/t_s、V_P＝L1/t_p(unit: m/s), L1 is very small, about 10 cm;

calculating the wave velocity of the Rayleigh wave, respectively recording the arrival time tn of the acceleration peak values of a plurality of acceleration sensors, and if the number of the acceleration sensors is n, the linear distance between two adjacent acceleration sensors is L2, the distance between the first acceleration sensor and the last acceleration sensor is (n-1) L2, and the wave velocity of the Rayleigh wave is calculated

In this embodiment, three acceleration sensors are provided, and the acceleration peak arrival times of the three acceleration sensors are t₁，t₂，t₃Wave velocity of surface wave Rayleigh wave

5. Correlation relation between three wave velocities, compacted soil density and soil medium material characteristics

Substituting the obtained surface wave velocity and shear wave velocity into formulaThe Poisson ratio of the compacted soil can be obtained; poisson's ratio and soil density substitution formulaThe elastic modulus of the compacted soil body can be obtained; substituted typeThe shear modulus of the compacted soil body can be obtained.

In the formula: v_PVelocity of longitudinal wave, m/s

V_SSpeed of transverse wave, m/s

V_RRayleigh wave velocity, m/s

Rho-density of wave propagation medium, kg/m³

E-modulus of elasticity, kPa

G-shear modulus, kPa

mu-Poisson's ratio

The measured wave velocity and the soil density are brought into a correlation relationship to obtain the elastic modulus, the shear modulus and the Poisson ratio of the compacted soil at the corresponding measuring position, and the compaction characteristics of the whole roadbed project can be obtained through multipoint tests;

6: the Beidou positioning system is combined, point-measured roadbed compaction characteristic information (a distance compaction characteristic) is transmitted to the data management system in real time, visual processing of the characteristics of the road base material after compaction is completed, further compaction characteristic information of a construction full section is reflected, body wave measurement is in the depth direction, the driving depth of each construction is kept the same, surface waves are in the surface direction, multi-angle detection can be more comprehensive, after fillers are paved, compaction is performed layer by layer, monitoring is performed in each compaction process, and the whole section is monitored in time, so that the compaction characteristic information of the construction full section can be reflected; and monitoring whether the roadbed compaction quality meets the requirements or not according to the construction specifications, storing the data to a big data platform, guiding the construction process, and providing a basis for a quality tracing system.

Nothing in this specification is said to apply to the prior art.