CN213867734U

CN213867734U - Standard penetration test device

Info

Publication number: CN213867734U
Application number: CN202022618290.XU
Authority: CN
Inventors: 王�章
Original assignee: Shanghai Shannan Surveying Design Co ltd
Current assignee: Shanghai Shannan Surveying Design Co ltd
Priority date: 2020-11-13
Filing date: 2020-11-13
Publication date: 2021-08-03
Anticipated expiration: 2030-11-13

Abstract

The utility model relates to a standard penetration test device, including punching hammer, drilling rod and mark and pass through the ware, drilling rod fixed connection marks and passes through the ware, first strain sensor is established to the upper end of drilling rod, the drilling rod passes through second strain sensor fixed connection mark and passes through the ware, first strain sensor and second strain sensor signal connection director. Compared with the prior art, the method can accurately measure the energy loss in the standard penetration process, directly convert the standard penetration number and obtain a more accurate result.

Description

Standard penetration test device

Technical Field

The utility model belongs to the technical field of the standard penetration test and specifically relates to a standard penetration test device is related to.

Background

The Standard Penetration Test (SPT) is a kind of dynamic penetration test, and is a method for measuring the bearing capacity of sand or cohesive soil foundation on site.

The standard penetration test equipment mainly comprises a standard penetration device, a drill rod and a core-through hammer. The drill rod is generally 42mm in diameter and the through hammer weighs 63.5 kg. During the test, the drop distance of the punching hammer is 76cm, so that the punching hammer freely falls, and the standard penetrating device is directly driven into the soil layer by 15 cm. And the standard penetration number of each 30 cm of soil layer is counted as the actual measurement standard penetration number N. When the length of the drill rod is more than 3 meters, the length of the drill rod needs to be corrected by calculating the standard penetration number.

In the standard penetration test, the drill rod is hit by the through-center hammer, energy is transmitted to the lower part standard penetration device, the energy is transmitted essentially, the energy in the transmission process is attenuated to a certain extent through the drill rod, the length of the drill rod is corrected by the Newton's collision theory at present, the weight of the drill rod is required to be not more than 2 times of the weight of the through-center hammer, and the length of the standard drill rod is limited to be less than 21 m. However, with the development of engineering construction, the depth of an exploration hole is larger and larger, the depth of a standard penetration requirement is larger and larger, and with the increase of the depth, the deviation between an actual measured standard penetration value corrected by the length of a drill rod and an actual value is further and further, and the existing standard penetration test equipment cannot meet the requirements of current engineering application.

SUMMERY OF THE UTILITY MODEL

The present invention is directed to a SPT apparatus for overcoming the above-mentioned drawbacks of the prior art.

The purpose of the utility model can be realized through the following technical scheme:

the utility model provides a standard penetration test device, includes punching hammer, drilling rod and mark and pass through the ware, drilling rod fixed connection marks and passes through the ware, first strain transducer is established to the upper end of drilling rod, the drilling rod passes through second strain transducer fixed connection mark and passes through the ware, first strain transducer and second strain transducer signal connection director.

The lower end of the piercing hammer is provided with a hammer pad.

The hammer pad is a metal hammer pad.

The guide rod passes through the punching hammer.

The first strain sensor and the second strain sensor are in wireless connection with the controller.

The first strain sensor and the second strain sensor are both resistance type strain sensors.

The first strain sensor and the second strain sensor are both BX120-3AA strain sensors.

The controller is a computer.

Compared with the prior art, the utility model has the advantages of it is following:

(1) through installing first strain sensor and second strain sensor, can the loss of accurate measurement standard penetration in-process energy, directly carry out the conversion of standard penetration number, compare traditional drilling rod length correction system, it is more direct, the result is also more accurate.

(2) The length limit of an original standard drill rod can be broken through, the diameter of the drill rod which is subjected to standard penetration in the original standard requires 42mm, the length of the drill rod is not more than 21m, and by adopting the testing device, the standard penetration number can be directly calculated through energy attenuation without being limited by the diameter of the drill rod and the length of the drill rod.

(3) By accurately determining the penetration number of the soil layer, engineering personnel can accurately know the soil property, the foundation design of the engineering foundation is facilitated, the engineering safety is improved, the self characteristics of the soil layer are fully utilized, the engineering design scheme is optimized, the engineering cost is reduced, and good social and economic benefits are achieved.

Drawings

Fig. 1 is a schematic structural view of the present invention;

reference numerals:

1 is a punching hammer; 2 is a guide rod; 3 is a hammer pad; 4 is a first strain sensor; 5 is a drill rod; 6 is a second strain sensor; and 7 is a standard penetration device.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

Examples

The embodiment provides a standard penetration test device, as shown in fig. 1, including a piercing hammer 1, a drill rod 5 and a standard penetration device 7, the drill rod 5 is fixedly connected with the standard penetration device 7, a first strain sensor 4 is arranged at the upper end of the drill rod 5, the drill rod 5 is fixedly connected with the standard penetration device 7 through a second strain sensor 6, and the first strain sensor 4 and the second strain sensor 6 are in signal connection with a controller.

Specifically, the method comprises the following steps:

the lower end of the piercing hammer 1 is provided with a metal hammer pad, and the piercing hammer 1 is 63.5 kg; the guide rod 2 penetrates through the punching hammer 1, and the length of the guide rod 2 is 76 cm.

The first strain sensor 4 and the second strain sensor 6 are connected with a controller through wifi on site, and the controller can be a computer on a test site.

The first strain sensor 4 and the second strain sensor 6 are both resistance type strain sensors, and the model is BX120-3 AA.

The details of the standard penetrometer 7 are prior art: the split pipe has an outer diameter of 51mm, an inner diameter of 35mm, a length of more than 457mm, a lower end length of 76mm, an edge angle of 18-20 degrees and a pipe boot with a thickness of 1.6mm at the end part of the cutting edge.

The using method comprises the following steps:

the through hammer 1 falls from the height of 76cm, penetrates the standard penetration device 7 into the soil layer through the drill rod 5, the first strain sensor 4 and the second strain sensor 6 respectively transmit the pressure information of two positions to the computer, and the computer calculates the loss in the energy transmission process by combining the pressure information, so that the standard penetration number conversion is carried out, the actual standard penetration number of the soil layer is accurately measured, and the problem that the standard penetration number is inaccurate due to the fact that the drill rod is too long is avoided.

Claims

1. The utility model provides a standard penetration test device, includes punch hammer (1), drilling rod (5) and passes through ware (7), drilling rod (5) fixed connection passes through ware (7), its characterized in that, first strain sensor (4) are established to the upper end of drilling rod (5), drilling rod (5) are through second strain sensor (6) fixed connection passes through ware (7), first strain sensor (4) and second strain sensor (6) signal connection director.

2. A benchmarking apparatus according to claim 1, wherein the lower end of the through-center hammer (1) is provided with a hammer pad (3).

3. A SPT apparatus according to claim 2, wherein said pad (3) is a metal pad.

4. A SPT device according to claim 1, wherein the guide rod (2) passes through the through-center hammer (1).

5. A SPT apparatus according to claim 1, wherein the first strain sensor (4) and the second strain sensor (6) are wirelessly connected to the controller.

6. A SPT apparatus according to claim 1, wherein the first strain sensor (4) and the second strain sensor (6) are both resistive strain sensors.

7. The SPT apparatus of claim 6, wherein said first strain sensor (4) and said second strain sensor (6) are each BX120-3AA strain sensors.

8. The SPT apparatus of claim 1, wherein the controller is a computer.