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Test device and method for judging soil layer collapsibility

A test device and technology of collapsibility, which is applied in the field of test devices for determining the collapsibility of soil layers, and can solve problems such as the inability to determine the sampling depth, the failure to penetrate the soil exploration point, and the unpredictable thickness of the collapsible soil layer. , to achieve the effect of obvious superiority, small size and simple operation

Inactive Publication Date: 2012-08-15
LANZHOU UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In actual operation, the thickness of collapsible soil layers in some sites can be estimated by referring to the existing geotechnical engineering data of adjacent sites to determine the sampling depth of exploratory wells; Indoor geotechnical test, which makes it impossible to determine the sampling depth when sampling the exploratory well. After the indoor test, the exploratory well has been backfilled, so that the soil exploration point cannot penetrate the collapsible loess layer.

Method used

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  • Test device and method for judging soil layer collapsibility
  • Test device and method for judging soil layer collapsibility
  • Test device and method for judging soil layer collapsibility

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Such as figure 1 and figure 2 As shown, this example provides a test device for judging the collapsibility of the soil layer, including an outer sleeve 12, a push rod 10 and a data processor 8 connected sequentially from the conical probe 16, and the outer sleeve 12 is a hollow cylindrical metal The body is made of heat-treated stainless steel (40Cr) material with a thickness of 5mm, its diameter can be 3-5cm, preferably 4.5cm in diameter, and its height is 7-10cm, preferably 9cm; the push rod 10 is heat-treated A hollow circular tube made of stainless steel (40Cr) material, the external diameter of the circular tube is 1.5cm, and the internal diameter is 1cm. The push rod 10 can be connected end to end and continuously connected to continuously press the conical probe 16 into the soil layer; the conical probe 16 is a solid cone, which is made of heat-treated stainless steel (40Cr), and has electronic components such as a soil moisture detector and a stress sensor in...

Embodiment 2

[0054] This example provides a test method for judging the collapsibility of the soil layer. When the test device described in Example 1 is used in this example, the resistance of the undisturbed loess cone 17 at a certain depth can be measured first, and the natural water content can be calculated. Lower the strength of the loess, and then fill the soil around the cone tip 17 to saturation, then measure the resistance of the soil cone 17 at this time, and compare the strength change of the soil before and after saturation to determine whether the soil layer is collapsible loess.

[0055]The specific implementation process of the present invention is to apply a force to the push rod 10 at the tail of the test device, and press the conical probe 16 into the soil at a constant speed. The probe sensor generates a resistance change signal, which will be transmitted to the data processor 8 on the ground. Under different soil layer conditions, the penetration resistance is differen...

Embodiment 3

[0058] In this example, within the survey depth range of 40.00m, the main formation is composed of silty loess, as follows:

[0059] 1. When in use, use a certain penetration pressure to press the conical probe 16 into the soil at a constant speed, and the intrusion rate of the conical probe 16 is controlled between 0.015 and 0.025m / s. When the conical probe 16 is in contact with the soil during the penetration process, it will generate penetration resistance, and the probe sensor will generate a resistance change signal, which will be transmitted to the measuring instrument on the ground.

[0060] 2. The resistance strain gauge 2 and the sensor 3 in the conical probe 16 will transmit the changing resistance signal to the data collector through the cable 5 for automatic recording. The depth of each penetration is 20cm, and then the resistance and the resistance of the cone tip 17 are obtained. deep relationship.

[0061] 3. After measuring the resistance of the cone tip 17 at...

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Abstract

The invention provides a test device and method for judging soil layer collapsibility. The test device comprises an outer sleeve, a push rod and a data processor, which are sequentially connected from a conical probe; a soil moisture detector and a stress sensor are arranged in the conical probe; the soil moisture detector comprises a load resistor and a moisture sensor and is used for detecting the water content in the soil body; the stress sensor comprises a strain gauge and a support column and is used for measuring the penetration resistance of the conical probe; and a water injection device is also arranged in the test device and used for simulating the critical water content in the strength test of a soil body. The test device provided by the invention is small in volume, is easy to operate and can be applied to the primary judgment of the loess collapsibility; the test device can primarily determine the interface between the collapsibility soil layer and the non-collapsibility soil layer and the thickness of the collapsibility soil layer without excavating or sampling the field oil layer, so as to determine the lower-limit depth of the collapsibility soil layer and further determine the sampling depth of the exploratory well in reconnaissance; and the test device has obvious superiority in large-area soil property investigation.

Description

technical field [0001] The invention relates to the field of geotechnical engineering testing, in particular to a testing device for judging the collapsibility of soil layers and a testing method thereof. Background technique [0002] In the design of construction projects in collapsible loess areas, the type of subsidence, the level of subsidence, and the boundary between plane and depth are directly related to the selection of the foundation of the building and the method of treatment of the foundation, and of course it is also related to the foundation of the foundation. The construction period, cost and quality assurance. The national standard "Code for Buildings in Collapsible Loess Areas" requires that "there should be a certain number of controllable soil-borrowing exploration points penetrating the collapsible loess layer" in the field survey section on the depth of exploration points. In actual operation, the thickness of collapsible soil layers in some sites can b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N33/24
Inventor 张豫川张可张森安辛明静高毅
Owner LANZHOU UNIVERSITY
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