- 摘 要
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(中鐵第四勘察設(shè)計院集團有限公司， 武漢 430063)
［摘要］大型石化工程地基處理難度高且復(fù)雜，開展了15 000，12 000，8 000，5 000kN·m能級單點強夯和群夯的超孔隙水壓力現(xiàn)場試驗。通過在不同能級試驗區(qū)內(nèi)不同位置和深度處埋設(shè)孔隙水壓力計，觀測并分析不同能級下強夯超孔隙水壓力變化規(guī)律。結(jié)果表明：相同地質(zhì)條件下，15 000，12 000kN·m能級單點強夯超孔隙水壓力消散90%需約40min，8 000，5 000kN·m能級需30min；5 000kN·m能級單點強夯水平影響距離約為5～6m，12 000，8 000，5 000kN·m能級單點強夯水平影響距離為7～8m。群夯后，淺層超孔隙水壓力基本大于深層超孔隙水壓力，超孔隙水壓力消散時間也相對較長，且淺層孔隙水壓力受群夯影響的水平距離較深層的大；當(dāng)場地內(nèi)存在黏性土夾層時，超孔隙水壓力消散時間增加，且消散速度與夾層厚度有關(guān)，需根據(jù)夾層厚度適當(dāng)調(diào)整間歇期（每遍夯擊時間間隔），夾層厚度大于2m時，15 000kN·m能級間歇期建議為3d，12 000，8 000，5 000kN·m間歇期建議為2d；群夯15 000，12 000，8 000，5 000kN·m能級有效加固深度分別大于11，10，8，8m。
［關(guān)鍵詞］軟弱地基土； 單點強夯； 群夯； 能級； 孔隙水壓力； 現(xiàn)場試驗
中圖分類號：TU472-3文獻(xiàn)標(biāo)識碼：A文章編號：1002-848X(2020)02-0138-06
Field test of pore water pressure during different energy-level dynamic compactions on soft foundation
Cao Liqiao
（China Railway Siyuan Survey and Design Group Co., Ltd., Wuhan 430063, China）
Abstract:The foundation treatment of large-scale petrochemical engineering is difficult and complex, and field single point dynamic compaction and group compaction tests of 15 000，12 000，8 000，5 000kN·m level of excess pore water pressure were carried out. By embedding pore water pressure gauge at different positions and depths in different energy level test area, the variation laws of excess pore water pressure in dynamic compaction under different energy levels were observed and analyzed. The results show that under the same geological conditions, the excess pore water pressure dissipation of 90% of 15 000kN·m and 12 000kN·m level single point dynamic compaction takes about 40min, and the excess pore water pressure dissipation of 8 000kN·m and 5 000kN·m level single point dynamic compaction takes about 30min. The horizontal influence distance of 5 000kN·m level single point dynamic compaction is about 5～6m, and the horizontal influence distance of 12 000, 8 000 and 5 000kN·m level single point dynamic compaction is 7～8m. After group compaction, the pressure of excess pore water in shallow layer is basically higher than that in deep layer, and the dissipation time of excess pore water pressure is relatively long, and the horizontal distance of excess pore water pressure affected by group compaction is larger than that in deep layer. When there is a clay interlayer in the field, the dissipation time of excess pore water pressure increases, and the dissipation speed is related to the thickness of interlayer. It is necessary to adjust the interval period according to the thickness of interlayer (interval time of each compaction). When the interlayer thickness is greater than 2m, the interval period of 15 000kN·m energy level is recommended to be 3 days, and the interval period of 12 000, 8 000 and 5 000kN·m is recommended to be 2 days. The effective reinforcement depth of 15 000, 12 000, 8 000 and 5 000kN·m level is greater than 11, 10, 8 and 8m respectively.
Keywords:soft foundation soil; single point dynamic compaction; group compaction; energy level; pore water pressure; field test
*中國石油工程建設(shè)公司科學(xué)研究與技術(shù)開發(fā)項目（CPECC2011KJ22）。
作者簡介：曹力橋，碩士，高級工程師，Email:caoliqiao52025@163.com。
