湖南大学学报(自然科学版)
湖南大學學報(自然科學版)
호남대학학보(자연과학판)
JOURNAL OF HUNAN UNIVERSITY(NATURAL SCIENCES EDITION)
2015年
5期
92-98
,共7页
地基处理%高填方路堤%桩网复合地基%土拱效应%桩土应力比
地基處理%高填方路隄%樁網複閤地基%土拱效應%樁土應力比
지기처리%고전방로제%장망복합지기%토공효응%장토응력비
foundation treatment%high fill embankment%pile-net composite foundation%soil arch effect%pile-soil stress ratio
针对高填方段软土路基在路堤荷载下桩网复合地基的受力特点,分析了其自上而下的荷载传递机理。首先,将路堤简化为内外土柱,通过内外土柱的整体微分平衡关系,得到了等沉面高度的理论计算式,由此较为合理地模拟了高填方段的土拱效应。而后,针对荷载传递至土工垫层阶段,采用薄膜模拟了桩土之间的荷载分配关系。在此基础上,将桩网复合地基划分为众多土工格栅、桩及桩间土单元体,桩体及桩间土简化为弹性支撑,进一步得到了高填方段桩网复合地基桩土应力比计算式。最后,对影响高填方段桩网复合地基桩土应力比的各主要影响参数进行了初步研究。结果表明,桩土应力比随路堤高度增大逐渐减小,即填土高度增加后桩土荷载分配趋于均匀,而桩间距、填土的压缩模量的增大将导致桩土应力比增加。此外,土工格栅抗拉强度的增大将加大桩土应力比值,但影响幅度较小。
針對高填方段軟土路基在路隄荷載下樁網複閤地基的受力特點,分析瞭其自上而下的荷載傳遞機理。首先,將路隄簡化為內外土柱,通過內外土柱的整體微分平衡關繫,得到瞭等沉麵高度的理論計算式,由此較為閤理地模擬瞭高填方段的土拱效應。而後,針對荷載傳遞至土工墊層階段,採用薄膜模擬瞭樁土之間的荷載分配關繫。在此基礎上,將樁網複閤地基劃分為衆多土工格柵、樁及樁間土單元體,樁體及樁間土簡化為彈性支撐,進一步得到瞭高填方段樁網複閤地基樁土應力比計算式。最後,對影響高填方段樁網複閤地基樁土應力比的各主要影響參數進行瞭初步研究。結果錶明,樁土應力比隨路隄高度增大逐漸減小,即填土高度增加後樁土荷載分配趨于均勻,而樁間距、填土的壓縮模量的增大將導緻樁土應力比增加。此外,土工格柵抗拉彊度的增大將加大樁土應力比值,但影響幅度較小。
침대고전방단연토로기재로제하재하장망복합지기적수력특점,분석료기자상이하적하재전체궤리。수선,장로제간화위내외토주,통과내외토주적정체미분평형관계,득도료등침면고도적이론계산식,유차교위합리지모의료고전방단적토공효응。이후,침대하재전체지토공점층계단,채용박막모의료장토지간적하재분배관계。재차기출상,장장망복합지기화분위음다토공격책、장급장간토단원체,장체급장간토간화위탄성지탱,진일보득도료고전방단장망복합지기장토응력비계산식。최후,대영향고전방단장망복합지기장토응력비적각주요영향삼수진행료초보연구。결과표명,장토응력비수로제고도증대축점감소,즉전토고도증가후장토하재분배추우균균,이장간거、전토적압축모량적증대장도치장토응력비증가。차외,토공격책항랍강도적증대장가대장토응력비치,단영향폭도교소。
According to the mechanical characteristics of pile-net composite foundation of high fill sec-tion of soft soil subgrade under embankment load,this paper made an in-depth analysis of the load transfer mechanism from the top to the bottom.Firstly,embankment soil was simplified as an inside and outside column.Then,according to integral differential balance between the inside and the outside soil column, the height of the initial plane of equal settlement can be derived and the soil arch effect of high embankment fill can be reasonably simulated.Secondly,when the load transfers to the geotechnical cushion layer,thin film is used to simulate the load distribution between the pile and the soil.Based on the results of previous derivations,pile-net composite foundation can be divided into geogrid,pile and soil elements between the pile bodies.The pile and the soil between the piles were simplified as an elastic support.The pile-soil stress ratio calculation formula of the high fill section pile-net composite foundation can be derived.Final-ly,this paper studied the main influence parameters of the pile-net composite foundation pile-soil stress ra-tio in the high fill section.The results show that,with the increase of embankment height,the pile-soil stress ratio decreases,namely,with the increase of fill height pile and soil,the load distribution tends to be more uniform,but the increase of pile spacing or the compression modulus will increase the pile-soil stress ratio.Furthermore,the increase of geogrid tensile strength will cause the increase of pile-soil stress ratio,but the influence of geogrid tensile strength is small.