CN106759216B - A kind of penetrometer and its measurement method having both dynamic sounding and static sounding - Google Patents

Abstract

The invention discloses a penetrometer with both dynamic penetration testing and static penetration testing, comprising an outer probe rod, an inner probe rod, an electric bridge box, a data acquisition instrument, and a computer. The outer probe rod is wrapped in the inner probe rod outside, and is in sliding contact with the outer wall of the inner probe rod, and the upper end of the inner probe rod has an extended part of the inner probe rod that is not wrapped by the outer probe rod, and the bottom end of the inner probe rod is provided with a miniature cone, which includes The friction cylinder connected to the bottom of the rod, the side wall friction sensor installed inside the friction cylinder, and the cone tip sensor installed at the bottom of the friction cylinder; the side wall friction sensor and the cone tip resistance sensor are all connected to the bridge box through cables , the bridge box is connected with the data acquisition instrument, and the data acquisition instrument is connected with the computer. The invention solves the problems that the traditional railway track structure safety design testing instrument is bulky, has large disturbance, difficult supporting conditions, inaccurate testing and the like.

Description

A penetrometer with both dynamic penetration testing and static penetration testing and its measurement method

technical field

The invention relates to a new penetrometer with both dynamic penetrability and static penetrability for testing the mechanical properties of soil on railway track subgrade, which belongs to the field of geotechnical engineering railway subgrade testing and has both dynamic and static penetrometer. detection device.

Background technique

With its advantages of safety, economy, and wide coverage, railway transportation will become the mainstream of transportation in the future, and the development and advancement of railway transportation technology will be accelerated. Large wheel loads, lateral pressure, strong traction and braking forces act on traditional railway lines, which will cause damage to the track structure and cause serious damage to passengers. So it is particularly important to evaluate the railway track structure.

Some nondestructive testing methods, such as the application of ground penetrating radar (GPR), have evaluated the ballast layer. Although ground penetrating radar (GPR) is efficient and cheap, it takes very little time in a large area, but the strength of the railway track structure Features cannot be evaluated. Lightweight Falling Weight Deflection (LFWD) and Loading Plate Testing (PBT) can be applied to railway track structures for static and dynamic load testing, but the only drawback is that when these methods are applied to subgrades, the ballast must be removed. In-situ test such as static penetration test (CPT), lateral pressure test (PMT), cross plate shear test (VST), standard penetration test (SPT), etc. Due to its large diameter probe rod and transmission rod, it is very important for railways. The orbital structure causes significant disturbances.

Contents of the invention

The purpose of the present invention is to provide a penetrometer with both dynamic penetrability and static penetrability, so as to solve the problems of traditional railway track structure safety design testing instruments, such as bulky, large disturbance, difficult supporting conditions, and inaccurate testing. .

To achieve the above object, the technical solution adopted in the present invention is:

A penetrometer with dynamic penetration testing and static penetration testing, comprising an outer probe rod, an inner probe rod, a bridge box, a data acquisition instrument, and a computer, the outer probe rod is wrapped on the outside of the inner probe rod, and The outer wall of the inner probe rod is in sliding contact, and the upper end of the inner probe rod has an extended part of the inner probe rod that is not wrapped by the outer probe rod. The bottom end of the inner probe rod is provided with a miniature cone. The friction cylinder, the side wall friction sensor arranged on the inner side of the friction cylinder, and the cone point sensor arranged at the bottom of the friction cylinder; the side wall friction sensor and the cone point resistance sensor are all connected to the bridge box through cables, and the bridge box It is connected with the data acquisition instrument, and the data acquisition instrument is connected with the computer.

The cross-sectional diameter of the micro cone is 15mm-25mm.

Both the side wall friction sensor and the cone tip resistance sensor are connected through four strain gauge full bridges.

Another object of the present invention is to provide a measurement method based on the above-mentioned penetrometer with both dynamic penetrability and static penetrability, the technical solution is as follows:

A measurement method based on the above-mentioned penetrometer with both dynamic penetrating sounding and static penetrating sounding, comprising the following steps:

Step 1: Install a vertical guide device on the ballast bed of the subgrade to be measured to ensure the verticality of the inner and outer probe rods of the penetrometer;

Step 2: Install the penetrometer in the middle of the vertical guide device, connect the drop hammer to the top of the penetrometer, and perform the dynamic penetrative testing process, the outer probe rod and the inner probe rod are coupled, and penetrate into the ballast bed at the same time; Record the hammering number and penetration depth to obtain the power penetration index;

Step 3: After the bottom layer of the ballast bed has been tested by power, the drop hammer and the vertical guide device are removed, and a penetration shell is installed on the outer extension of the inner probe rod to carry out the static penetration process;

Step 4: The inner probe rod is penetrated into the subgrade, and the penetration resistance is measured during the static penetrating process.

In the second step, the weight of the power penetration drop hammer is 110-120N, and the drop height is 570-590mm.

In the fourth step, the inner probe rod penetrates into the subgrade at a constant speed of 1-2mm/s.

In the fourth step, the measured penetration resistance includes the side wall friction resistance fs obtained from the test of the side wall friction resistance sensor, and the cone tip resistance qc obtained from the test of the cone tip resistance sensor.

Beneficial effects: the present invention solves the problems of traditional railway track structure safety design testing instruments such as bulky, large disturbance, difficult supporting conditions, and inaccurate testing. The new penetrometer has simple structure, good quality control, high repeatability, and has In-situ, multi-functional, automatic, fast, etc., suitable for in-situ dynamic testing of various geological soil layers, especially the underground structure of railway tracks, can in-situ test the parameters of various soil layers, and can quickly and effectively measure The engineering mechanical properties of railway track subgrade provide a powerful test tool for civil engineering exploration practice, especially railway track structure.

Description of drawings

Fig. 1 is the structural representation of penetrometer of the present invention;

Figure 2 is a schematic diagram of the vertical guide device for the drop hammer;

Fig. 3 is a schematic diagram of a dynamic penetrating probe device;

Figure 4 is a schematic diagram of the installation of the penetrating shell device before static penetration testing;

Figure 5 is a schematic diagram of the static penetrating device;

In the figure: 1-cable, 2-extended part of inner probe rod, 3-outer probe rod, 4-inner probe rod, 5-miniature cone, 6-side wall friction sensor, 7-friction cylinder, 8-cone tip resistance Sensor, 9-bridge box, 10-data acquisition instrument, 11-computer, 12-vertical guide device, 13-sleeper, 14-ballast bed, 15-subgrade, 16-drop hammer, 17-penetration shell, 18-reverse force device.

Detailed ways

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

As shown in Figure 1, a penetrometer with both dynamic penetrating and static penetrating probes of the present invention includes an outer probe rod 3, an inner probe rod 4, a bridge box 9, a data acquisition instrument 10, and a computer 11, The outer probe rod 3 is wrapped on the outside of the inner probe rod 4, and is in sliding contact with the outer wall of the inner probe rod 4, and the upper end of the inner probe rod 4 has an inner probe rod extension part 2 that is not wrapped by the outer probe rod 3, and the inner probe rod 4 A miniature cone 5 is provided at the bottom end of the inner probe 5, and the miniature cone 5 includes a friction cylinder 7 connected to the bottom end of the inner probe rod 4, a side wall friction sensor 6 arranged on the inner side of the friction cylinder 7, and a cone tip arranged at the bottom end of the friction cylinder 7. Sensor 8; the side wall friction sensor 6 and the cone resistance sensor 8 are all connected to the bridge box 9 through the cable 1, the bridge box 9 is connected to the data acquisition instrument 10, and the data acquisition instrument 10 is connected to the computer 11.

Among them, the outer probe rod 3 is used for power penetration into the ballast bed, and the micro-cone 5 is used for static penetration penetration into the subgrade. When the outer probe rod and the inner probe rod are not coupled, the inner probe rod penetrates alone for static penetration testing, and the penetration rate is 1-2mm/s; when the outer probe rod and the inner probe rod are coupled, the outer probe rod and the inner probe rod The probe rod penetrates at the same time for dynamic penetration testing.

The cross-sectional diameter of the miniature cone 5 is 15mm-25mm.

The side wall friction sensor 6 is used to test the side wall friction fs, and the cone tip resistance sensor 8 is used to test the cone tip resistance qc. They are connected to the bridge box through cables, and finally measure their values. Both the side wall friction sensor 6 and the cone tip resistance sensor 8 are tested through the full bridge connection of four strain gauges.

The above-mentioned penetrometer is used to measure the railway track structure, and the specific steps are as follows:

A method for measuring a penetrometer based on both dynamic penetration testing and static penetration testing, comprising the following steps:

Step 1: install a vertical guide device 12 on the ballast bed of the subgrade to be measured to ensure the verticality of the probe rod of the penetrometer; as shown in Figure 2;

Step 2: Install the penetrometer in the middle of the vertical guide device 12, and connect the drop weight 16 to the top of the penetrometer to carry out the process of dynamic penetration testing, as shown in Figure 3. During this process, the outer probe rod and The inner probe rod is coupled and penetrated into the ballast bed; the dynamic penetration index is obtained by recording the number of hammering and penetration depth;

Among them, the weight of the power penetration drop hammer is 110-120N, and the drop height is 570-590mm;

Step 3: After the bottom layer of the ballast bed has been explored by power, remove the drop hammer 16 and the vertical guide device 12, install a penetrating shell 17 on the extension part 2 of the inner probe rod, and install the penetrating shell 17 on the counter force device 18, As shown in Figure 4, the static penetration testing process is carried out;

Step 4: During the static penetration testing process, the inner probe rod penetrates into the subgrade at a constant speed of 1-2mm/s, as shown in Figure 5, to measure the penetration resistance, including the side wall friction resistance fs obtained by the side wall friction resistance sensor test , the cone resistance qc obtained from the cone resistance sensor test.

The test device retains and improves the function of conventional dynamic penetration testing, so that it has the function of static penetration testing, and can be used according to the adjustment of dynamic penetration testing and static penetration testing according to the soil layer, which solves the problem of traditional railway track structure safety design The test instrument is bulky, disturbed, the required supporting conditions are difficult, and the test is inaccurate. The in-situ dynamic test of various soil layers of different geology, especially the underground structure of the railway track, can test the parameters of various soil layers in situ, and can quickly and effectively determine the engineering mechanical properties of the railway track subgrade, which is especially useful for the practice of civil engineering exploration. It is a powerful testing tool for railway track structures.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also possible. It should be regarded as the protection scope of the present invention.

Claims (7)

1. A penetrometer with both dynamic penetrating and static penetrating, characterized in that it comprises an outer probe rod (3), an inner probe rod (4), a bridge box (9), a data acquisition instrument (10 ), a computer (11), the outer probe rod (3) is wrapped on the outside of the inner probe rod (4), and is in sliding contact with the outer wall of the inner probe rod (4), and the upper end of the inner probe rod (4) has not been The outer extension part (2) of the inner probe rod (3) wraps, and the bottom end of the inner probe rod (4) is provided with a miniature cone (5), and the miniature cone (5) includes the bottom end of the inner probe rod (4). The connected friction cylinder (7), the side wall friction sensor (6) that is arranged on the inner side of the friction cylinder (7), the cone tip sensor (8) that is arranged on the bottom end of the friction cylinder (7); the side wall friction sensor ( 6), the cone tip resistance sensor (8) is connected with the bridge box (9) through the cable (1), the bridge box (9) is connected with the data acquisition instrument (10), the data acquisition instrument (10) is connected with the computer (11 )connect. 2. The penetrometer with both dynamic penetration testing and static penetration testing according to claim 1, characterized in that: the cross-sectional diameter of the micro-cone (5) is 15mm-25mm. 3. The penetrometer with both dynamic CPT and static CPT according to claim 1, characterized in that: the side wall friction sensor (6) and the cone tip resistance sensor (8) pass through four Strain gauge full bridge connection. 4. A measuring method based on a penetrometer with both dynamic penetrating sounding and static penetrating sounding according to any one of claims 1-3, characterized in that: comprising the following steps: Step 1: Install a vertical guide device on the ballast bed of the subgrade to be measured to ensure the verticality of the inner and outer probe rods of the penetrometer; Step 2: Install the penetrometer in the middle of the vertical guide device, connect the drop hammer to the top of the penetrometer, and perform the dynamic penetrative testing process, the outer probe rod and the inner probe rod are coupled, and penetrate into the ballast bed at the same time; Record the hammering number and penetration depth to obtain the power penetration index; Step 3: After the bottom layer of the ballast bed has been tested by power, the drop hammer and the vertical guide device are removed, and a penetration shell is installed on the outer extension of the inner probe rod to carry out the static penetration process; Step 4: The inner probe rod is penetrated into the subgrade, and the penetration resistance is measured during the static penetrating process. 5. The measuring method according to claim 4, characterized in that: in the second step, the weight of the power penetration drop hammer is 110-120N, and the drop height is 570-590mm. 6. The measuring method according to claim 4, characterized in that in the fourth step, the inner probe rod penetrates into the subgrade at a constant speed of 1-2 mm/s. 7. The measuring method according to claim 4, characterized in that: in the fourth step, the measured penetration resistance includes the side wall friction fs obtained from the test of the side wall friction sensor, and the cone resistance fs obtained from the test of the cone tip resistance sensor. Tip resistance qc.