Design of foundation treatment for a seaside project

Li Tao

Abstract：?In?this?paper，two?80，000?cubic?meters?oil?storage?tanks?are?located?on?the?seaside?of?a?petrochemical?project.For?the?treatment?of?large?area?thick?layer?soft?soil?foundation?of?seashore，crushed?stone?pile?is?used?to?compound?it，and?then?it?is?pre-pressed?by?stages?and?then?the?foundation?treatment?scheme?is?designed.

1.Engineering?survey

A?petrochemical?project，located?on?the?seaside，plans?to?build?two?80，000?cubic?meters?of?oil?tanks，which，according?to?planning?requirements，are?being?built?at?the?same?time.The?diameter?of?the?oil?tank?is?80?m，the?height?of?the?oil?tank?is?20?m， the?distance?between?the?two?tanks?is?120?m，the?net?distance?between?the?two?tanks?is?40?m，the?weight?of?the?filling?body?is?about?25?000?KPA，the?corresponding?base?pressure?is?72?KPA， the?maximum?height?of?oil?storage?is?16，and?the?maximum?pressure?of?the?tank?base?is?270?KPA.According?to?the?deformation?control?requirements?of?the?oil?tank?equipment?for?the?foundation，the?plane?inclination?（any?direction） is?not?greater?than?3/1000，the?uneven?settlement?of?the?tank?circumference?is?less?than?25?mm?per?10m， and?the?slope?of?the?cone?surface?of?the?tank?foundation?is?obtained.No?less?than?8/1000?and?the?settlement?difference?between?the?center?and?the?edge?of?the?tank?is?less?than?280?mm.

2.Foundation?treatment?scheme?optimization

The?80，000?m?3oil?tank?is?80?m?in?diameter?and?the?maximum?pressure?of?the?base?is?270?kpa，and?the?site?is?mainly?composed?of?thick?layer?soft?soil，the?strength?and?deformation?of?which?obviously?cannot?meet?the?requirements?of?80?000?m?3large?tank?foundation，so?the?foundation?treatment?must?be?carried?out..

According?to?the?engineering?geological?conditions?of?the?site，the?third?layer?of?sandy?silty?soil?is?judged?to?be?moderate?to?severe?liquefaction，so?anti-liquefaction?treatment?must?be?carried?out，and?the?liquefaction?of?the?inland?foundation?soil?in?the?pile?length?range?can?be?eliminated?by?setting?the?gravel?pile?in?the?foundation.The?influence?depth?of?liquefaction?of?foundation?soil?during?earthquake?can?be?considered?in?the?range?of?15m?below?the?ground，so?the?pile?length?of?gravel?pile?can?be?taken?15m.After?being?treated?with?gravel?pile，the?bearing?capacity?of?the?composite?foundation?can?reach?110?kpa， which?still?can?not?meet?the?requirements?of?270kpa?of?80?000?m?3oil?tank?foundation. Therefore， it?is?necessary?to?further?strengthen?the?oil?tank?foundation?by?water?filling?preloading?method.Table?1?It?can?be?seen?that?the?52nd?layer?of?the?site?is?silty?soil?layer?with?a?depth?of?about?25m.Therefore，the?plastic?drainage?belt?of?26m?can?enter?52?layers，using?the?horizontal?permeability?of?this?layer?to?play?the?role?of?two-way?drainage.

After?comprehensive?consideration，it?was?decided?that?the?combined?treatment?of?80?000?m?3oil?tank?foundation?with?compacted?gravel?pile?composite?foundation?and?plastic?drainage?zone?water?filling?preloading?method?was?adopted.The?layout?of?gravel?piles?is?shown?in?figure?1-1.

4.Conclusion

The?design?length?of?gravel?pile?is?15m，the?design?length?of?plastic?drainage?belt?is?26m，so?the?calculation?of?foundation?consolidation?parameter?is?also?divided?into?three?sections，the?first?is?the?length?of?gravel?pile，the?second?is?the?distance?from?the?bottom?of?gravel?pile?to?the?bottom?of?plastic?drainage?belt，the?second?section?is?the?distance?from?the?bottom?of?gravel?pile?to?the?bottom?of?plastic?drainage?belt，and?the?calculation?of?foundation?consolidation?parameter?;is?also?carried?out?in?three?sections. The?third?section?is?the?distance?from?the?bottom?of?the?plastic?drainage?belt?to?the?bottom?of?the?compression?layer，26?m?/ 40?m.At?the?same?time，bout?100mm?distance?was?inserted?from?the?grouting?pipe?to?the?bottom?of?the?hole，and?the?grouting?pipe?was?pulled?out?while?grouting?at?the?edge?of?the?hole.When?the?orifice?flowed?out?of?the?cement?slurry，it?stopped?after?6?days?and?8?days?later. After?6?days，the?cement?slurry?was?finally?condensed， and?the?sealing?of?the?hole?orifice?was?carried?out?again，and?the?secondary?grouting?was?carried?out?until?it?was?saturated.Grouting?water?The?ash?ratio?is：0.4?to?0.45; bound?to?the?200?mm?reinforced?mesh?of?the?6@200mm;the?C30?concrete?is?sprayed?to?the?thickness?of?100?mm，the?spacing?of?the?crushed?stone?piles?is?s?= 1.5m，and?the?pile?length?is?taken?as?L?= 15?m?in?consideration?of?the?requirements?for?liquefaction?treatment?of?the?foundation?soil.

reference documentation

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