公路交通技术
公路交通技術
공로교통기술
TECHNOLOGY OF HIGHWAY AND TRANSPORT
2014年
2期
1-4
,共4页
复合地基%堆载预压%超孔隙水压力%桩土应力%固结度
複閤地基%堆載預壓%超孔隙水壓力%樁土應力%固結度
복합지기%퇴재예압%초공극수압력%장토응력%고결도
composite foundation%preloading%excess pore water pressure%pile-soil stress%degree of consolidation
对高铁站场咽喉区深厚软土大面积堆载预压下复合地基的工程力学与变形特性开展现场试验研究，分析不同位置和深度的超孔隙水压力、沉降变形以及桩土应力等参数随时间和填土高度的变化规律。研究结果表明：1)高铁站场咽喉区复合地基内的超孔隙水压力随着荷载增加而增大，达到峰值后，随时间延长而逐渐消散，其变化略滞后于荷载的变化；超孔隙水压力的最大值出现在下卧层上部，此处附加应力也较大；在下卧层中，随着深度增加，超孔隙水压力逐渐减小。2)高铁站场咽喉区复合地基由路堤中心向外，桩应力、桩间土应力及桩土应力比总体呈减小趋势。在路堤填筑和预压中，站场咽喉区复合地基桩间土应力向桩传递，桩间土应力逐渐减少，桩顶应力逐渐增大，并逐渐趋于稳定。
對高鐵站場嚥喉區深厚軟土大麵積堆載預壓下複閤地基的工程力學與變形特性開展現場試驗研究，分析不同位置和深度的超孔隙水壓力、沉降變形以及樁土應力等參數隨時間和填土高度的變化規律。研究結果錶明：1)高鐵站場嚥喉區複閤地基內的超孔隙水壓力隨著荷載增加而增大，達到峰值後，隨時間延長而逐漸消散，其變化略滯後于荷載的變化；超孔隙水壓力的最大值齣現在下臥層上部，此處附加應力也較大；在下臥層中，隨著深度增加，超孔隙水壓力逐漸減小。2)高鐵站場嚥喉區複閤地基由路隄中心嚮外，樁應力、樁間土應力及樁土應力比總體呈減小趨勢。在路隄填築和預壓中，站場嚥喉區複閤地基樁間土應力嚮樁傳遞，樁間土應力逐漸減少，樁頂應力逐漸增大，併逐漸趨于穩定。
대고철참장인후구심후연토대면적퇴재예압하복합지기적공정역학여변형특성개전현장시험연구，분석불동위치화심도적초공극수압력、침강변형이급장토응력등삼수수시간화전토고도적변화규률。연구결과표명：1)고철참장인후구복합지기내적초공극수압력수착하재증가이증대，체도봉치후，수시간연장이축점소산，기변화략체후우하재적변화；초공극수압력적최대치출현재하와층상부，차처부가응력야교대；재하와층중，수착심도증가，초공극수압력축점감소。2)고철참장인후구복합지기유로제중심향외，장응력、장간토응력급장토응력비총체정감소추세。재로제전축화예압중，참장인후구복합지기장간토응력향장전체，장간토응력축점감소，장정응력축점증대，병축점추우은정。
This paper develops on-site experimental research on engineering mechanical and deformation characteristics of composite foundations under large-area preloading of deep and thick soft soil in throat area of high-speed railway stations, and analyzes change rules of parameters such as excess pore water pressure, sedimentation deformation and pile-soil stress, etc. with time and depth of fill so as to provide a scientific basis for design and construction of similar projects. The results of research show that:1 ) The excess pore water pressure in composite foundations in throat area of high-speed railway stations increases with load, and dissipates gradually with prolonged time, and its change slightly lags behind change of load;the maximum value of excess pore water pressure appears on the top of underlying stratum where additional stress is also large; in underlying stratum excess pore water pressure decreases gradually with increase of depth. 2 ) In composite foundations in throat area of high-speed railway stations, from the center of embankment to outside pile stress, soil stress between piles and pile-soil stress ratio shows a tendency of decrease in general. In fill and preloading of embankment, the soil stress between piles in composite foundations in throat area of stations transfers to piles and decreases gradually, and the stress on the top of piles increases and tends towards stability gradually.
