Variable-head soft clay consolidation model test box and use method thereof

Abstract

The invention discloses a variable-head soft clay consolidation model test box and a use method thereof, and belongs to the technical research field of submarine pipelines in ocean engineering. The device is composed of a consolidation system, a vacuum pump and a high-definition camera, the consolidation system comprises a free water bucket, a model box and a water collection bucket, the free water bucket is placed at a certain height of the upper part of the model box and is connected with the model box through a pipeline, and free water in the bucket flows into the model box under the action of water head pressure; the side face of the model box is made of organic glass facilitating observation of soil deformation, the bottom of the model box is provided with a water outlet connected with a water collecting barrel, the water collecting barrel is a sealed water barrel made of high-strength steel, and the front side and the rear side of the water collecting barrel are each provided with a connector connected with the model box and the vacuum pump. The vacuum pump exhausts air from the water collecting barrel to generate negative pressure, and free water in the soft clay is sucked into the water collecting barrel under the suction force of the negative pressure; the high-definition camera is arranged right in front of the model box and used for shooting deformation of a soil body in a model test. Free water in the soft clay is promoted to vertically and downwards seep through the combined action of water head pressure and negative pressure suction, rapid solidification of the soft clay is achieved, and the in-situ shear strength of a soil body is achieved.

Description

technical field [0001] The invention relates to the technical field of marine engineering submarine pipeline research, in particular to a variable head soft clay consolidation model test box and a use method thereof. Background technique [0002] The subsea pipeline undergoes large buckling deformation under the action of temperature stress during oil and gas transportation, in which vertical arching and lateral sliding are the main buckling modes. The protection and buckling deformation control are of great significance. The interaction mechanism between submarine pipeline and foundation soil is the most important content of research. Relevant researchers need to study the model boxes used for model tests. [0003] Soft clay and silt soil are the most common foundation soils on the seabed. The interaction mechanism between them and pipelines is the focus of pipeline research. However, the permeability of cohesive soils is much lower than that of sandy soil foundations, an...

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Problems solved by technology

However, the water collection efficiency of this system is low only by negative pressure suction, which is not enough to consolidate the muddy soil with poor permeability to the expected shear strength, and the friction between the model test box and the end of the pipeline has great influence on the test results. large error, so the system is not suitable for experimental research on submarine pipelines

[0006] CN 107916662A, CN 102116022A, CN 108005058A and CN 108277794A respectively disclose treatment methods for soft soil foundations, by embedding multiple vertical drainage bodies in soft soil foundations, pumping water through pumps, vibrating or lateral pressurization, etc. Accelerates the consolidation of soft soil foundations, however, vertical drainage divides the foundation soil into several subregions in model tests, and these methods cannot produce a homogeneous foundation soil

Therefore, it cannot be applied to small-scale model tests

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