HomeDirect Vacuum Preloading
Release time：Jul 24,2023
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The vacuum pressure transmission path in conventional vacuum preloading is: vacuum device → main pipe → filter pipe → sand cushion → plastic drainage board → reinforcement of soil. During the transmission process, vacuum pressure is subjected to the damping effect of sand cushion, filter tube, and filter membrane, resulting in significant energy loss. The measured data shows that the outlet pressure of the vacuum device can reach over 95kPa. When it reaches the sand cushion through the main pipe and filter tube, the vacuum pressure is generally 80-85kPa. The vacuum pressure in the drainage plate gradually decreases with depth, and the decrease is relatively large.
In order to reduce the loss of vacuum pressure along the way, the direct vacuum preloading method has adjusted the transmission path of vacuum pressure: vacuum device → main pipe → branch pipe → connecting hose → plastic drainage plate → reinforcement of soil. The key link is to eliminate the horizontal sand cushion, filter tube, and The loss of Vacuum energy by the filter membrane keeps the vacuum pressure reaching the plastic drainage plate at about 80kPa, and the loss along the depth is small, which improves the utilization efficiency of vacuum pressure, thus shortening the reinforcement time and improving the reinforcement effect. In addition, due to the elimination of horizontal sand cushion, the engineering cost is reduced.
The direct vacuum preloading significantly improves the energy efficiency of vacuum preloading, that is, the vacuum pressure of the direct vacuum preloading at different depths of the drainage board is 10-50% higher than that of conventional vacuum preloading, and the deeper the depth, the more significant the effect; The settling rate of direct vacuum preloading is about 30% higher than that of conventional vacuum preloading, and the average total settling amount of direct vacuum preloading is 49.3% higher than that of conventional vacuum preloading, shortening the preloading time; At the same time, the soil reinforced by the direct vacuum preloading method has better physical and mechanical indicators than the conventional vacuum preloading method, and does not require a medium coarse sand cushion, saving materials and reducing engineering costs.
