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1、第11卷第6期鐵道科學(xué)與工程學(xué)報(bào)Volume11Number62014年12月JournalofRailwayScienceandEngineeringDecember2014砂樁-網(wǎng)復(fù)合地基2次預(yù)壓沉降計(jì)算方法①陳宏偉,徐林榮,左糰(中南大學(xué)土木工程學(xué)院,湖南長(zhǎng)沙410075)摘要:京滬高速鐵路昆山試驗(yàn)段技術(shù)升級(jí)改造,時(shí)隔5a后對(duì)原有砂樁-網(wǎng)復(fù)合地基進(jìn)行2次預(yù)壓,能否滿足高速鐵路工后沉降控制要求成為關(guān)鍵問題。分析了砂樁地基固結(jié)變形規(guī)律,利用模糊數(shù)學(xué)(Fuzzy)理論的“升半柯西分布”,建立隸屬度函數(shù)描述砂樁-網(wǎng)復(fù)合地基從固結(jié)排水到復(fù)合地基的轉(zhuǎn)化程度,提出固結(jié)度表達(dá)式,并通過實(shí)測(cè)數(shù)據(jù)
2、驗(yàn)證該表達(dá)式計(jì)算精度。并對(duì)考慮土體應(yīng)力歷史影響的e-lgp曲線法計(jì)算2次預(yù)壓沉降量進(jìn)行探討,該方法可最終實(shí)現(xiàn)工后沉降精確估算。關(guān)鍵詞:砂樁-網(wǎng)復(fù)合地基;2次預(yù)壓;固結(jié)度;升半柯西分布;工后沉降中圖分類號(hào):TU443文獻(xiàn)標(biāo)志碼:A文章編號(hào):1672-7029(2014)06-0058-04Calculationmethodofsettlementforthesandpiles-netcompositefoundationundersecondarypreloadconditionsCHENHongwei,XULinrong,ZUOShen(SchoolofCivilEngineerin
3、g,CentralSouthUniversity,Changsha410075,China)Abstract:DuetotechnologyupgradingoftheBeijing-Shanghaihigh-speedrailwayinKunShantestsection,theoriginalsandpiles-netcompositefoundationwasperformedwithsecondarypreloadingafterfiveyears'operation.Thekeyproblemwaswhethercontrolrequirementscouldmeetth
4、erequirementsofhigh-speedrailwaysettlementafterpreloading.Inthispaper,thedeformationlawofconsolidationofthesandpilesfoundationwasanalyzedusingthetheoryofFuzzymathematics(Fuzzy)“Semi-CauchyDistribution”,throughestablishingmembershipfunctiontodescribethesandpiles-netfromtheconsolidateddrainedc
5、onditiontotheconversiondegreeofcompositefoundation.Inthiscase,theequationofconsolidationdegreewasproposedandthecalculationprecisionwasvalidatedthroughmeasureddata.Finally,thismethodcanachievepreciseestimationofsettlementafterconstruction,byconsideringtheeffectofthesoilstresshistorywithe-lgpcu
6、rvemethodtocalculatethemagnitudeofsettlementaftersecondarypreloading.Keywords:sandpiles-netcompositefoundation;secondarypreloading;degreeofconsolidation;semi-cauchydistribution;settlementafterconstruction砂樁-網(wǎng)復(fù)合地基是我國(guó)應(yīng)用比較早的一種道,工后沉降控制標(biāo)準(zhǔn)提高至≤15mm,在不改變散體樁復(fù)合地基,適用于擠密松散砂土、粉土、黏性砂樁-網(wǎng)復(fù)合地基加固措施的基礎(chǔ)上,原試驗(yàn)段進(jìn)土等地
7、基處理,被廣泛應(yīng)用于道路與鐵道工程以及行了2次堆載預(yù)壓。能否滿足高速鐵路工后沉降房建工程等基礎(chǔ)建設(shè)中。砂樁研究成果較豐富,在控制要求成為工程關(guān)鍵,因此對(duì)長(zhǎng)期靜置(5a)后[1-3][4-6][7-9]施工工藝、加固機(jī)理、設(shè)計(jì)計(jì)算等方進(jìn)行2次預(yù)壓的砂樁-網(wǎng)復(fù)合地基沉降計(jì)算精度面都有較成熟的理論與實(shí)踐經(jīng)驗(yàn)。京滬高速鐵路提出了很高的要求,現(xiàn)有砂樁沉降計(jì)算方法主要應(yīng)[10-12]昆山試驗(yàn)段原設(shè)計(jì)采用有砟軌道,一般路基的工后用港灣、公路、房建等領(lǐng)域,計(jì)算精度難以滿沉