真空預(yù)壓發(fā)處理軟土地基施工方案英文版(參考版)
2025-05-13 14:47本頁(yè)面
【正文】 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 can be increased to (Pp – PV) and the consolidation effect would be improved as a result. The process of vacuum pound with preloading method is shown in drawing “ The Process drawing of Vacuum Prepression bined with Loading Method” in page 10. Monitoring method The loading height and loading period of each step of general area is mainly controlled by the stability of the foundation soil. The settlement monitoring should be mainly concerned in this area. Because the vacuum prepression method will not cause a soil stability problem, the site measurements have less significance parable to preloading method. According to the requirement of the tender documents, settlement gauges should be installed at 50mx50m grid and be measured by leveling instruments. The total settlement and settlement speed of the foundation in the loading area as well as the settlement or the rising height in the surrounded area must be monitored. The final settlement S? can be calculated from the site monitoring data. The consolidation settlement Sc and the average consolidation r
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