真空预压和堆载预压加固机场软基效果对比

Comparison of Reinforcement Effect of Vacuum Preloading and Surcharge Preloading on Airfield Soft Foundation

依托浦东机场四期扩建地基处理试验段工程,开展了大面积软土地基真空预压和堆载预压试验。基于地基表面沉降、分层沉降、孔隙水压力,以及水平位移的变化规律,比较了真空预压和堆载预压加固软基效果。结果表明,真空预压和堆载预压对机场软土地基加固效果均较好,地表沉降量可达到1000 mm左右,淤泥质黏土层沉降值可达到30 cm左右。抽真空与堆载过程中孔隙水压力变化较大,预压结束后黏土层存在孔隙水压力残留。真空预压水平位移较大,约占沉降的40%,堆载预压区域外土体易发生隆起变形,需严格控制堆载速率。

Based on the foundation treatment test of the fourth extension in Pudong Airport,the vacuum preloading and surcharge preloading tests of a large area of soft ground were carried out.Based on the variation law of ground surface settlement,stratified settlement,pore water pressure and horizontal displacement,the reinforcement effect of vacuum preloading and surcharge preloading on soft foundation was compared.The results show that both vacuum preloading and surcharge preloading have good effects on the reinforcement of the soft soil foundation of the airport.The surface settlement can reach about 1000 mm,and the sedimentation value of the silt clay layer can reach about 30 cm.The pore water pressure changes greatly during the process of vacuuming and loading,and the pore water pressure remains in the clay layer after the end of preloading.The horizontal displacement of vacuum preloading is large,accounting for about 40%of the settlement.The soil outside the preloading area is prone to uplift,so the loading rate should be strictly controlled.