WO2010072133A1

WO2010072133A1 - On-site detector for foundation bearing capacity and filling compactness

Info

Publication number: WO2010072133A1
Application number: PCT/CN2009/075762
Authority: WO
Inventors: 常博功; 卢国亮; 胡石
Original assignee: 沈阳市建科仪器研究所
Priority date: 2008-12-23
Filing date: 2009-12-21
Publication date: 2010-07-01
Also published as: CN101476314A; CN101476314B

Abstract

An on-site detector for foundation bearing capacity and filling compactness comprises: a casing(2), a crossbeam(1), a load sensor(5), a displacement guide sleeve(11), a transmission shaft(7), a sounding rod(8), a sounding head(9), a data acquisition processor(4), a control and display panel(10), a communication interface(6) and a power supply box(3), in which, the transmission shaft(7), the sounding rod(8) and the sounding head(9) are connected to the bottom of the load sensor(5) fixed in the inner cavity of the casing(2). The signals generated by the load sensor(5), which change as the sounding head(9) is being inserted into soil mass, will be sampled, amplified, calculated and displayed by the data acquisition processor(4), and be sent to the host computer through the communication interface(6) for intelligent processing.

Description

Ground bearing capacity filling density field tester

[Technical Field]

A site-based bearing capacity compactness field tester involves the exploration, design, construction and other fields of geotechnical engineering. It is used to describe and evaluate the load strength of natural foundation, determine the compactness of artificial foundation, water content and other soils. Mechanical indicators. 【Background technique】

In the practice of geotechnical engineering, we often come into contact with natural foundations and artificial backfilled foundations. For the evaluation of the particle size, density distribution, load strength and water content of such soils, the critical state and limit state are determined. It will directly affect and control the quality of construction projects. It is a century-old plan for national capital construction. Therefore, it is essential to conduct on-site quantitative and qualitative analysis of the compactness of foundation bearing capacity.

Among the existing related technologies, there is A: "Electronic micro-piercing instrument" refers to the Chinese patent: 88216921.1 - produced by Shenyang Institute of Automation, the principle: mechanical spring to do the force measuring element, the probe length lcm. The shortcomings are: After the spring fatigue, the error increases. Because the probe is only 1cm long, the sounding is limited and cannot be tested in situ. It is necessary to take out the soil sample by drilling, which increases the disturbance and water loss of the soil. B: The "soil penetration resistance meter" produced by the United States refers to the American Standard D1558-99 (2004) American Geotechnical Testing Materials Association. The principle is: pure mechanical structure, spring as the force measuring component, and the scale shows the result. The shortcomings are: The visual error of the scale display itself exceeds ± 5%, and the error of the spring after the load cell is fatigued increases, and the data disappears after the scale is retracted and cannot be retained. C: "Nuclear Density Meter" See <Geotechnical Test Procedures>, SL237-1999 Section 4 - Sheng Shuxin, Tao Xiuzhen, Xu Bomeng of Nanjing Institute of Hydraulic Research, etc., Principle: Application of gamma rays and electrons around the atom of matter For elastic collisions, Compton scattering occurs, and the greater the density of the soil, the greater the attenuation of gamma rays. Therefore, the principle of calculating the density of the soil can be calculated by measuring the change in the intensity of the gamma rays before and after entering the soil. The shortcomings are: Since the xenon ray source is composed of cobalt 60 (CO ⁶⁰ ) and cesium 137 (CS ¹³⁷ ), it is well known that radiation to the human body is harmful to the environment, so it is protective, anti-radiation, special care, safety. The facilities are very complicated. D: "Grinding method" see <Geotechnical Test Procedures>, SL237-1999 Section 2 - Sheng Shuxin, Tao Xiuzhen, Xu Bomeng of Nanjing Hydraulic Research Institute. The principle: Digging and sand filling method is to use the equivalent weight, volume of standard sand and compacted solid soil weighing method to calculate the density of earth. The shortcomings: labor intensity, time-consuming, costly and laborious.

[Summary of the Invention]

The object of the present invention is to provide a device which is small in size, portable and capable of controlling construction quality in the field: Ground bearing capacity filling density field detector, the purpose of this solution is to solve the problems in the prior art. (1. Radiation nuclear pollution, 2. Soil disturbance caused by drilling and soil testing, water loss, 3. Increased error after spring fatigue, 4. Visual error of scale itself, 5. Data disappears after scale retraction cannot be retained, 6. Digging and sand filling method takes a lot of time and money).

The solution to achieve this goal is: a beam-load sensor, a drive shaft, a probe, a probe, a data acquisition The set processor-control display panel-communication interface is combined to form a special instrument for on-site detection of foundation bearing capacity filling density.

Its technical features: The pressure is applied to the top of the T-shaped beam, so that the rigid contact probe drives the probe to penetrate vertically into the soil. While the probe is forced into the soil by the force, the soil exerts a reaction force on the probe, and the peripheral friction of the probe to the soil is excluded. Usually, the resistance of the tip acting on the probe is called the penetration resistance of the soil. The harder the soil, the less water content, the higher the density, the higher the strength, and the greater the penetration resistance. The opposite is also true. Using this principle, we can select the contact probe with sufficient stiffness and diameter to obtain the penetration resistance of different soils at the same depth, so as to obtain the mechanical indexes such as load strength, water content and density distribution inside the soil. The test results are input to The data acquisition processor performs calculation, enlargement, display, storage, and printing to form engineering reports, and realizes intelligent modern construction quality management.

The characteristic benefits of the invention: 1. Replace the mechanical scale reading value, avoid visual error and improve the precision. 2. Because it is equipped with a long touch probe, it is not necessary to drill the soil. It can be in situ tested, without disturbance and without losing water, and maintain the soil mechanics of the natural state of the soil. 3. Nuclear-free testing, no radiation nuclear contamination. 4. Replacing the sand-filling method, saving a lot of manpower and material resources to shorten the construction period. In the past, it took several hours to measure the density by sand-filling method, and it takes a few minutes to measure a point with the invention, and the social benefits are considerable. 5. Apply real-time dynamic tracking, peak retention, mean calculation, and direct formation of engineering reports to the data acquisition processor of the single-chip microcomputer to realize intelligent modern construction quality management.

[Description of the Drawings]

Figure 1: Mechanical components of the ground bearing capacity compactness field tester

Figure 1: 1 beam, 2 chassis, 3 power box, 4 data acquisition processor, 5 load sensor, 6 communication interface, 7 drive shaft, 8 touch probe, 9 touch probe, 10 control display panel, 11 displacement guide set.

【detailed description】

Figure 1 is an embodiment of the design: a special 2 chassis systemically combines a 5 load sensor-mechanical conduction system (7 drive shaft, 8 touch probe, 9 touch probe) - 4 data acquisition processor The utility model has a T-shaped cross beam at the top of the casing, a load sensor fixed at the center of the inner cavity of the casing, a displacement guiding sleeve at the bottom of the casing, a data acquisition processor, a power supply box and a machine in the casing A control display panel and a communication interface are mounted on the casing of the casing. The load cell is connected to the drive shaft and then connected to the probe and the probe.

The touch probe in Figure 1 is designed as a single-section and multi-segment structure according to the detection requirements. The segments are connected by threads, keyways and nails. The surface of each touch probe is provided with a displacement depth scale.

The shape of the touch probe in Figure 1 is designed to be conical, cylindrical, pyramidal, with diameters of Φ4.52, Φ 6.4, Φ 9.7, 16.5, angles of 20°, 30°, 60°, 180°.

The power supply box in Figure 1 is equipped with a power supply box on the grid inside the casing. The two types of batteries for charging and non-charging are general. The data acquisition processor in Figure 1 uses a low-voltage ultra-low-power single-chip controller. a highly integrated operational amplifier The crystal display realizes real-time sampling, comparison, calculation, tracking display of the load signal of the load sensor, and sends the input and output signals to the communication interface.

The working process of the invention is: pressing the beam on the top of the instrument, the load sensor is subjected to force deformation, and the probe is penetrated into the soil through the probe, and the physical layer of the soil layer is detected according to the resistance of the tip of the probe in the penetration soil. The mechanical properties, in order to establish the correlation between the penetration resistance PS and the bearing capacity fa and the compactness person and the compressive inductance E _S . An embodiment of the design: Taking a conical probe as an example: a formula for the bottom cross-sectional area, penetration depth and penetration resistance of the conical probe during penetration: Ps = P/A

Where: P _S - soil penetration resistance

P-soil ratio penetration resistance

A—the bottom cross-sectional area of the conical probe

H—the depth of penetration of the probe into the soil

Fa—the foundation allows the bearing capacity

E _S - soil compression measurement

Λ—the compactness of the soil

Shear strength of R-soil

Since the penetration resistance can be continuously measured along the insertion depth, the stratified qualitative analysis of the soil can be performed by using the variation curve of the penetration resistance Ρ with the penetration depth h, thereby identifying the clay soil, the silty clay, The sandy soil further determines the bearing capacity of each bearing layer based on the penetration resistance Ps, the compressive amount of soil E _S , the compactness of the soil λ, and the shear strength of the soft clay.

The detection result measured by the load sensor is sent to the data acquisition processor for sampling, amplification, storage, real-time dynamic tracking, maximum peak retention, average value, and a result display, and the data is sent to the terminal communication interface, and the upper computer is formed. The report has thus completed a complete set of modern construction quality inspection and office intelligent management.

Claims

Rights request

1. Ground bearing capacity compactness field tester, including: casing, beam, load sensor displacement guide sleeve, drive shaft, touch probe, touch probe, data acquisition processor, control display panel, communication interface, power supply A box or the like is characterized in that: the load sensor is combined with a data acquisition processor, a control display panel, a drive shaft, a probe, and a touch probe.

2. The ground bearing capacity compactness field tester according to claim 1, wherein: the top of the casing has a T-shaped handle beam, and the bottom end of the casing is fixed with a displacement guiding sleeve.

3. The ground bearing capacity compactness field tester according to claim 1, wherein: a load sensor is installed in a middle portion of the inner cavity of the casing. The bottom end of the load cell is connected to the drive shaft, the probe and the touch probe piece by piece.

4. The ground bearing capacity compactness field tester according to claim 1, wherein: a data acquisition processor, a power box, and a control display panel and a communication interface are arranged in the casing.

5. The ground bearing capacity compactness field tester according to claim 1, wherein: the touch probe is divided into a single section and a multi-segment structure, and each section is connected by a thread, a keyway, and a nail, each of which is connected. The surface of the feeler probe is provided with a displacement depth scale.

6. The ground bearing capacity compactness field tester according to claim 1, wherein the touch probe is divided into three types: a conical shape, a pyramidal shape, and a cylindrical shape.