Large freezing test model box and simulation test platform

Abstract

The present invention relates to a large freezing test model box and large freezing simulation test platform. The platform comprises: a groundwater circulation system, a formation simulation system, arefrigeration cycle system and a monitoring system, therein the formation simulation system is used to simulate distribution of different soil layers, the groundwater circulation system is used to simulate different groundwater flow rates, and the refrigeration cycle system is used to simulate the formation freezing construction scheme under different working conditions, and the monitoring systemis used to record a change trend of each monitoring quantity during a freezing process. The large freezing test model box and simulation test platform can simulate groundwater flow in a test soil layer to the greatest extent, analyse temperature field expansion and variation law through automatic data acquisition and processing, and study forming process of frozen walls (curtains) or bottom plates, determine thickness control variables, and obtain relationship between groundwater flow rate and freezing temperature field and freezing design parameters, and optimize freezing design scheme, andpropose corresponding measures.

Description

technical field [0001] The invention relates to the field of artificial freezing model tests, in particular to a large-scale multi-functional freezing test model box and a test platform. The test platform is used by similar simulation theory to simulate the influence of the groundwater seepage velocity in the actual formation on the freezing project, and to analyze the impact of the groundwater seepage on the freezing temperature field. And the influence and mechanism of the frozen wall characteristics. Background technique [0002] In modern cities, there are dense buildings on the ground and various underground pipelines. The method of artificial precipitation will have a huge impact on buildings and pipelines. Not only that, due to urban policy reasons, many cities such as Beijing have drawn a large amount of water during the construction process. Groundwater will cause huge economic losses. In addition, in the face of the current lack of water resources in cities, the me...

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Problems solved by technology

However, the flowing groundwater will take away the cold energy in the freezing pipe. With the increase of the groundwater flow rate, the freezing wall crossing time will gradually increase until it cannot cross the circle, which will lead to freezing failure.

In the past, researches on freezing usually did not consider the influence of groundwater flow rate on freezing engineering. There are two reasons: first, the frozen volume is small, and the cooling capacity supply is sufficient, and too high a local flow rate will not affect the overall freezing effect; second, the formation permeability coefficient small, making it difficult for the groundwater flow rate to reach the threshold of 5m / d given by the code

However, in the thick sand and pebble stratum (-30~-80m) in the Beijing area, it is easy to cause the freezing failure of the underground water flow rate in the subway station water stop project. Therefore, it is necessary to invent a large-scale multi-functional freezing test platform. Study the relationship between the groundwater flow rate and the freezing temperature field and freezing design parameters, analyze the mechanism of the influence of groundwater seepage on the shape of the frozen wall, deduce the calculation formula of the thickness of the frozen wall and the average temperature under the condition of seepage through the model test platform, and give the groundwater The influence of flow velocity on the freezing temperature field provides important support for later numerical simulation analysis and engineering guidance

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