岩土力学
巖土力學
암토역학
Rock and Soil Mechanics
2015年
11期
3268-3274
,共7页
灌注桩套管%高频振动%挤土效应%有限元
灌註樁套管%高頻振動%擠土效應%有限元
관주장투관%고빈진동%제토효응%유한원
sleeve for cast-in-place pile%high frequency vibration%squeezing effect%finite elements
随着全套管振动取土灌注桩施工工艺的发展，灌注桩在工程中的应用越来越广泛，但关于灌注桩套管高频振动贯入机制，特别是套管贯入引起的挤土效应研究还不全面。全面介绍了套管高频振动贯入全过程的有限元-无限元耦合模型的建立过程后，对地表隆起、土体侧移及超孔隙水压力等挤土效应的变化规律进行了详细研究。研究结果表明：水平向的挤土位移随套管贯入深度的增加而增大，竖向挤土位移随着套管贯入深度的增加，浅层土表现为隆起量增大，而深层土表现为下沉量增大；最大挤土位移与套管贯入深度存在滞后效应；浅层土体的隆起为水平向应力加载引起竖向应力增加所致，且隆起分界面深度随着动力荷载幅值增大而增大，随振动频率的增大而减小；超孔隙水压力随套管贯入深度增加而增大，随径向距离增大呈指数型衰减。
隨著全套管振動取土灌註樁施工工藝的髮展，灌註樁在工程中的應用越來越廣汎，但關于灌註樁套管高頻振動貫入機製，特彆是套管貫入引起的擠土效應研究還不全麵。全麵介紹瞭套管高頻振動貫入全過程的有限元-無限元耦閤模型的建立過程後，對地錶隆起、土體側移及超孔隙水壓力等擠土效應的變化規律進行瞭詳細研究。研究結果錶明：水平嚮的擠土位移隨套管貫入深度的增加而增大，豎嚮擠土位移隨著套管貫入深度的增加，淺層土錶現為隆起量增大，而深層土錶現為下沉量增大；最大擠土位移與套管貫入深度存在滯後效應；淺層土體的隆起為水平嚮應力加載引起豎嚮應力增加所緻，且隆起分界麵深度隨著動力荷載幅值增大而增大，隨振動頻率的增大而減小；超孔隙水壓力隨套管貫入深度增加而增大，隨徑嚮距離增大呈指數型衰減。
수착전투관진동취토관주장시공공예적발전，관주장재공정중적응용월래월엄범，단관우관주장투관고빈진동관입궤제，특별시투관관입인기적제토효응연구환불전면。전면개소료투관고빈진동관입전과정적유한원-무한원우합모형적건립과정후，대지표륭기、토체측이급초공극수압력등제토효응적변화규률진행료상세연구。연구결과표명：수평향적제토위이수투관관입심도적증가이증대，수향제토위이수착투관관입심도적증가，천층토표현위륭기량증대，이심층토표현위하침량증대；최대제토위이여투관관입심도존재체후효응；천층토체적륭기위수평향응력가재인기수향응력증가소치，차륭기분계면심도수착동력하재폭치증대이증대，수진동빈솔적증대이감소；초공극수압력수투관관입심도증가이증대，수경향거리증대정지수형쇠감。
With the development of the technique for constructing the cast-in-place piles with high frequency vibratory hammers, the cast-in-place piles have been widely used in construction engineering. The penetration mechanism of the pile sleeve driven by high frequency vibratory hammers remains unclear, and particularly the squeezing effect in the sleeve penetration has yet to be investigated. In this paper, a finite elements and infinite elements coupling model is developed for simulating the sleeve penetration process driven by high frequency vibratory hammers, and used to study the squeezing effects such as ground heaves, lateral soil displacement and excess pore pressure generation. The results indicate that the horizontal displacement induced by soil compaction increases with the increase of sleeve penetration depth, and for the vertical compaction displacement, the heave increases in shallow soil layers and the settlement increases in deep soil layers as the sleeve penetration depth increases. The maximum compaction displacement lags behind the sleeve penetration depth. The reason for heave in shallow soil layers is that the horizontal stress increment causes an increase in the vertical stress, and the depth of heave interface increases with the increase of dynamical load amplitude, while decreases with the increase of vibration frequency. The excess pore pressure increases with the increase of sleeve penetration depth, and exhibits an exponential attenuation trend as the radial distances increases.
