关键词: 吹填砂土地基, 高能级强夯, 标准贯入试验, 静力触探试验, 平板载荷试验

Abstract: During coastal blowing and filling of sandy soil foundation, high water table levels and soft interlayers are often encountered, which results in the difficulty to reinforce the ground. In order to study the reinforcement effect of high energy dynamic compaction on this type of soil, a field test of high energy dynamic compaction with 6 000 kN·m and 8 000 kN·m energy levels on a blow-filled sandy soil along the coast of Shandong was conducted. After the test, standard penetration test,static cone penetration test and plate loading test were used for on-site inspection. Through analyzing, the number of SPT strokes and the tip resistance of CPT were significantly increased in the depth range required by the design before and after the dynamic compaction, indicating that high energy dynamic compaction is very effective in eliminating the liquefaction potential of saturated sand and saturated chalk soil. Through the PLT p-s curve and the relationship formula of the tip resistance standard value and the bearing capacity characteristic value, the bearing capacity characteristic value ≥ 120 kPa after dynamic compaction was obtained, proved the feasibility of the high energy dynamic scheme. The impacts of the position of the soft soil interlayer and the height of the water table were studied; And it was found that the soft soil layer impeded the transfer of the dynamic energy and reduced the effective reinforcement depth of dynamic compaction, and the different position of the soft soil layer had different influence on the effect of dynamic compaction:When there was a soft soil layer at the critical area affected by dynamic compaction, the effective reinforcement depth was at the top of the soft soil layer. In the field test of high energy dynamic compaction with 4 000 kN·m energy level, the effective reinforcement depth reached 5 m after dynamic compaction without precipitation; However, with the precipitation of 3 m below ground level, after dynamic compaction the effective reinforcement depth reached 7 m. On the basis of high energy level dynamic research,a high energy level ramming was carried out in a large area of 750 000 square meters, and it was found that the treated foundation met the requirements of the construction site.

Key words: hydraulic sandy fill, high energy level dynamic compaction, standard penetration test, static cone penetration test, plate loading test