Method for measuring liquefaction resistance of offshore submarine sediments in situ

Abstract

The invention discloses a method for measuring liquefaction resistance of offshore submarine sediments in situ. In the method, a measuring device is provided. The measuring process comprises a layingstep and a data acquisition step, in the laying step, S1, transporting the measuring device to a research target point position by an auxiliary boat, enabling a data module to work, connecting a lifting device with the measuring device through a mooring rope and a controllable hook, lifting the measuring device to a position above the research site position and keeping the measuring device to be vertical; S2, opening the controllable hook to enable the measuring device to penetrate into the offshore submarine sediments under the action of free gravity; in the recovering step, S3, after the measuring device penetrates into and is stable, recovering the measuring device through the lifting device; S4, acquiring penetration depth data and accelerated speed data. According to the method, the advantages of in-situ measuring methods such as SPT and CPT are synthesized, the liquefaction resistance of the offshore submarine sediments can be measured and evaluated effectively, and accurate dataand research basis are provided for prevention and control of coastal zone geological disaster.

Description

technical field [0001] The invention relates to a seabed sediment detection method, belonging to the field of seabed geological engineering, in particular to an in-situ measurement method for the liquefaction resistance of offshore seabed sediments based on the principle of free fall. Background technique [0002] Marine sediment refers to the general term for seabed sediments formed by various marine depositions. The substances deposited on the seabed with seawater as the medium. The causes of deposition include various physical, chemical and biological factors. The formation of these sediments The process is often not carried out in isolation, and most of them are geological bodies produced by comprehensive effects. Traditionally, sediments are divided according to the depth of seawater in the area: 0-20 meters are nearshore deposits, 20-200 meters are shallow-sea deposits, 200-2000 meters are semi-deep-sea deposits, and more than 2000 meters are deep-sea deposits. [000...

AI Technical Summary

Problems solved by technology

The standard penetration method is not accurate enough, and can only make preliminary judgments on the liquefaction resistance; the static penetration method has high requirements for the specifications of the measuring equipment and auxiliary ships; the physical and mechanical parameters of the laboratory are tested after the original samples are obtained by drilling , and based on the existing liquefaction evaluation formula or numerical model, although it has high accuracy, the operation process is more cumbersome and complicated, and this method is easy to change the physical and mechanical state of the sediment at the original position, and then affect the test results

Therefore, the existing discrimination methods still have the problems of being labor-intensive, labor-intensive, and costly.

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