工程地质学报
工程地質學報
공정지질학보
2015年
2期
265-271
,共7页
冲填软土地基%深层地基加固%搅拌桩%微型桩%数值模拟
遲填軟土地基%深層地基加固%攪拌樁%微型樁%數值模擬
충전연토지기%심층지기가고%교반장%미형장%수치모의
Dredger fill of soft ground%Deep foundation reinforcement%Mixing pile%Micro-pile%Numerical simulation
冲填软土地基需要经过地基处理后才能投入工程使用，处理方案一般为浅层地基处理如真空预压处理，但对于大面积大荷载堆载场地，浅层地基处理不足以保证地基稳定性，需进一步做深层地基加固。本文针对广州某造船基地大面积堆载场地，对经真空预压处理后的该类深厚冲填软土地基提出了搅拌桩地基、微型桩地基以及搅拌桩微型桩交错布设地基加固方案，并基于Biot固结理论和有效应力原理，采用有限元分析软件PLAXIS进行数值模拟，对土体选取基于修正剑桥模型的软土模型和Mohr-Coulomb模型，对搅拌桩和微型桩依次选取线弹性模型和弹性模型，计算得到不同加固方案的基础沉降量。基于不同桩型加固机理对计算结果进行进一步分析得出，对此类深厚冲填软土地基，相同桩长的搅拌桩地基加固效果较微型桩效果更明显；另通过对不同桩长搅拌桩地基加固效果的模拟计算，发现桩长为10m到15m的搅拌桩均能有效加固地基，但随着桩长的增加，加固效果未能显著提高。本研究为冲填软土地基深层加固的设计提供了一定的依据。
遲填軟土地基需要經過地基處理後纔能投入工程使用，處理方案一般為淺層地基處理如真空預壓處理，但對于大麵積大荷載堆載場地，淺層地基處理不足以保證地基穩定性，需進一步做深層地基加固。本文針對廣州某造船基地大麵積堆載場地，對經真空預壓處理後的該類深厚遲填軟土地基提齣瞭攪拌樁地基、微型樁地基以及攪拌樁微型樁交錯佈設地基加固方案，併基于Biot固結理論和有效應力原理，採用有限元分析軟件PLAXIS進行數值模擬，對土體選取基于脩正劍橋模型的軟土模型和Mohr-Coulomb模型，對攪拌樁和微型樁依次選取線彈性模型和彈性模型，計算得到不同加固方案的基礎沉降量。基于不同樁型加固機理對計算結果進行進一步分析得齣，對此類深厚遲填軟土地基，相同樁長的攪拌樁地基加固效果較微型樁效果更明顯；另通過對不同樁長攪拌樁地基加固效果的模擬計算，髮現樁長為10m到15m的攪拌樁均能有效加固地基，但隨著樁長的增加，加固效果未能顯著提高。本研究為遲填軟土地基深層加固的設計提供瞭一定的依據。
충전연토지기수요경과지기처리후재능투입공정사용，처리방안일반위천층지기처리여진공예압처리，단대우대면적대하재퇴재장지，천층지기처리불족이보증지기은정성，수진일보주심층지기가고。본문침대엄주모조선기지대면적퇴재장지，대경진공예압처리후적해류심후충전연토지기제출료교반장지기、미형장지기이급교반장미형장교착포설지기가고방안，병기우Biot고결이론화유효응력원리，채용유한원분석연건PLAXIS진행수치모의，대토체선취기우수정검교모형적연토모형화Mohr-Coulomb모형，대교반장화미형장의차선취선탄성모형화탄성모형，계산득도불동가고방안적기출침강량。기우불동장형가고궤리대계산결과진행진일보분석득출，대차류심후충전연토지기，상동장장적교반장지기가고효과교미형장효과경명현；령통과대불동장장교반장지기가고효과적모의계산，발현장장위10m도15m적교반장균능유효가고지기，단수착장장적증가，가고효과미능현저제고。본연구위충전연토지기심층가고적설계제공료일정적의거。
Dredger fill of soft ground can't be put into engineering until foundation treatment is finished.Shallow foundation treatment such as vacuum preloading is generally utilized to improve the strength of foundation.But for a large area loading ground,shallow foundation treatment is not sufficient to ensure the stability of the foundation. Therefore,a deep foundation reinforcement is needed.Three plans of deep foundation reinforcement are the mixing pile foundation,micro-pile foundation and the mixture of the two piles.They are proposed after vacuum preloading treatment for the dredger fill of soft ground of the shipbuilding base in this paper.Besides,the finite element method software PLAXIS is utilized to simulate the proposed plans in the framework of the Biot's consolidation theory and the effective stress theory.Soft Soil Model based on the modified Cam-clay Model is selected for muck and mucky soil.Mohr-Coulomb Model is selected for sand,clay and silty clay.Linear elastic model and elastic model are respectively for mixing piles and micro piles.Settlements of different plans are obtained by the calculation.Further analysis on the different types of foundation reinforcement is made with different mechanism. For this deep dredger fill of soft ground,the mixing pile foundation is better than the micro-pile foundation with the same length in improving the ground strength.Additionally,settlements of mixing pile foundation with different lengths are calculated.The mixing pile foundation with the length from 1 0m to 1 5m can improve the ground strength.However,the effect is not improved obviously as the length increases.The results can provide some basis for the design of a deep dredger fill of soft ground reinforcement.
