Cone penetration test probe suitable for use in deep sea

Abstract

The invention discloses a cone penetration test probe suitable for use in deep sea, comprising a conical head and a pore pressure detection device. A pressure cavity is arranged in the probe; the conical head is provided with a water hole. The pore pressure detection device divides the pressure cavity into a front pressure cavity and a rear pressure cavity. The front pressure cavity is communicated with the water hole via a first water passage. The rear pressure cavity is communicated with the outside via a second water passage. The pore pressure detection device includes a first diaphragm, asecond diaphragm, a differential pressure measuring element and an absolute pressure measuring element. The cone penetration test probe herein has the advantages that the differential pressure sensorand the absolute pressure sensor complement each other; namely the differential pressure measuring element having small range but high resolution helps measure a difference between pore pressure and static pressure, so that measurement precision is improved; the absolute pressure measuring element having wide range but small resolution is used to measure static pressure of sea water, thereby facilitating in-situ calibration and giving a consideration to both measurement range and measurement precision.

Description

technical field [0001] The invention belongs to the field of in-situ testing of deep-water soil, and in particular relates to pore pressure static penetrating equipment in a high confining pressure environment. Background technique [0002] Pore ​​water pressure static penetration testing is a new type of in-situ testing technology that emerged internationally in the late 1970s and early 1980s. It combines the element for measuring pore water pressure with the standard static penetration probe, so that it can measure the excess pore water pressure of the soil generated during the penetration process while measuring the resistance of the cone tip and the friction of the side wall. Pore ​​pressure static sounding can be used to divide the soil layer, determine the type of soil layer, find out the uniformity of soft and hard interlayers and soil layers in the horizontal and vertical directions, and evaluate the engineering characteristics of foundation soil. [0003] At presen...

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Problems solved by technology

[0003] At present, most deep-water in-situ pore pressure equipment has to face the following potential problems: the contradiction between resolution and range (that is, the resolution is low when the range is large, and the range is small when the resolution is high, which cannot be taken into account), low precision, and inability to in-situ Calibration, etc.

Marine geotechnical engineering, especially deep sea geotechnical engineering, due to the large water depth, the static pore pressure u h This will lead to the fact that if ordinary sensors want to meet the range requirements, the resolution accuracy cannot be guaranteed

And when measuring the resistance of the cone tip and the friction of the side wall, if the design is not proper, the two forces will interact with each other, resulting in inaccurate measurement

[0004] The above problems will affect the accuracy of the measurement data

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