真空預(yù)壓發(fā)處理軟土地基施工方案英文版-文庫吧
2025-04-13 14:47 本頁面
【正文】 chieve the requirement of the specification for soil improvement philosophy of vacuum prepression method The vacuum prepression method is used to consolidate foundation soil. This method consists in laying on the surface of foundation soil a sand bed, and in installing a drainage system with wick drains. The sand bed drain line is buried and connected with vacuum system to form an air exhaust and a dewatering system. A set of airtight seal membranes is laid on the surface of the sand bed with its edge buried in soil. Thus, a negative pressure area within sand bed and foundation soil can be formed from air exhaust and dewaturing pumps. The vacuum method can reach a soil bearing capacity of 80KPa. Under the vacuum condition, soil is in the state of consolidating and pore water is discharged from soil under the pressure difference. The consolidation is pleted when pressure of soil to be consolidated is reaching the same pressure of the drainage system. The philosophy of vacuum repression method is that under the pressure difference (PaPv), soil can be consolidated。 Pa indicates atmospheric pressure and Pv indicates air pressure in the sand bed and the vertical drains. In the calculation of consolidation of the foundation soil, the RENDULICTERZAGE Theory and BICOT Theory of Consolidation can be adopted which are the same of those adopted in loading repression method. The drop of the ground water table may also accelerate the consolidation of foundation soil beside the pressure difference. The effective stress in the soil increases successively during the period of Proposed Design Philosophy, Construction, Installation and Monitoring Method As per of Section of ITB 3 3 consolidation of the foundation soil with vacuum repression method. The horizontal displacement of the soil is toward the center of the consolidation area from the beginning of the period of vacuum repression, which is different from the loading repression method. So the stability of the foundation soil will not bee a problem, and the required vacuum capacity can immediately be obtained and consequently, the period of vacuum repression can be curtailed. Details is shown in drawings “ Design Philosophy for Vacuum Prepression “ and “ Flow Diagram of Vacuum Prepression Method” in page 8, 9. Regarding the short work period of this project, the vacuum pound with loading repression method is used in the process area where the required bearing capacity of the foundation soil is 100 Kpa. It has been proved from the theoretical calculation and our previous experience that the effects of vacuum and loading repression methods on the consolidation can be coaxed. For this purpose, a soil capacity of 150 Kpa had been obtained in one of our previous project in the turbine house of Hiep Phuoc power plant located at Nha Be district in Hochiminh city. During the vacuum process and under the pressure difference (Pa – Pv), the pore water permeates into the vertical drains and the consolidation occurs. On the other hand, when using preloading method, the air pressure raises to Pp and the consolidation occurs under the pressure difference (Pp – Pa). Therefore, by using the vacuum pound with preloading method, the pressure
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