【摘要】：研究目的:樁側(cè)負(fù)摩阻力對樁產(chǎn)生下拽力,導(dǎo)致基樁沉降增大,豎向抗壓承載安全等級降低,甚至造成樁體破壞。為分析不同樁端下臥層(黃土和粗砂)對基樁沉降和負(fù)摩阻力的影響,本文通過室內(nèi)模型試驗(yàn),對比研究兩種下臥層情況下樁體、樁周土變形及樁身軸力分布的差異,明確基樁中性點(diǎn)位置的變化規(guī)律并給出建議值。研究結(jié)論:(1)下臥層對樁周土沉降的影響較小,但對樁身沉降的影響較大,相同堆載等級下粗砂下臥層的中性點(diǎn)位置明顯低于黃土下臥層;(2)兩種下臥層的樁身軸力都隨堆載等級的增大而增大,但粗砂下臥層的下拉荷載和樁端反力明顯大于黃土下臥層;(3)兩種下臥層情況下,依據(jù)樁土相對位移和樁身峰值軸力確定的中性點(diǎn)位置基本一致;(4)在實(shí)際工程中應(yīng)根據(jù)樁端下臥層的地質(zhì)情況,采取適當(dāng)措施,盡量減小基樁負(fù)摩阻力,充分發(fā)揮基樁的承載性能;(5)建議黃土下臥層中性點(diǎn)位置取0.51l~0.6l,粗砂下臥層可取0.6l~0.8l;(6)該研究成果可為類似工程堆載條件下樁基中性點(diǎn)的確定及設(shè)計(jì)提供一定的參考。
[Abstract]:The purpose of the study is that the negative friction on the side of the pile results in the downdraft force, which results in the increase of the settlement of the foundation pile, the decrease of the safety grade of the vertical compression bearing capacity, and even the destruction of the pile body. In order to analyze the influence of different pile end bedding (loess and coarse sand) on pile settlement and negative friction resistance, this paper compares the difference of pile body, soil deformation around pile and axial force distribution of pile body under two kinds of underlying layers by laboratory model test. The change rule of neutral point position of foundation pile is clarified and the suggested value is given. The conclusions are as follows: (1) the influence of the substratum on the soil settlement around the pile is small, but the influence on the settlement of the pile body is greater, and the neutral position of the substratum of coarse sand is obviously lower than that of the substratum of loess under the same grade of heaped load; (2) the axial force of pile body increases with the increase of pile load grade, but the pull-down load and pile tip reaction force of coarse sand substratum are obviously larger than that of loess substratum; (3) the position of the neutral point determined by the relative displacement of the pile and the peak axial force of the pile body is basically the same under the two kinds of horizontal layers; (4) appropriate measures should be taken to reduce the negative friction resistance of the pile in the actual engineering according to the geological conditions of the substratum of the pile end, so as to give full play to the bearing capacity of the pile; (5) it is suggested that the position of neutral point of loess substratum should be 0.51L / 0. 6l, and that of coarse sand substratum should be 0.6l0. 8l; (6) the research results can provide a certain reference for the determination and design of neutral point of pile foundation under similar engineering load condition.
【作者單位】： 蘭州交通大學(xué);
【基金】：國家自然科學(xué)基金資助項(xiàng)目(41562014)
【分類號】：TU473.1

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 李美霞;涂芬芬;;堆載預(yù)壓下下臥層的沉降量研究[J];山西建筑;2012年07期

2 解宏偉;下臥層沉降計(jì)算模型及邊界條件的確定[J];青海大學(xué)學(xué)報(bào)(自然科學(xué)版);2000年03期

3 張玉國,謝康和,王哲,莊迎春;未打穿砂井地基下臥層固結(jié)研究分析[J];巖土力學(xué);2005年11期

4 王鳳池;朱浮聲;張德海;;水泥攪拌樁地基下臥層沉降計(jì)算方法選擇[J];沈陽建筑大學(xué)學(xué)報(bào)(自然科學(xué)版);2006年05期

5 亓樂;王青松;劉薇;;剛性樁復(fù)合地基樁端向下臥層刺入量計(jì)算方法[J];地下空間與工程學(xué)報(bào);2014年03期

6 孔垂?fàn)T;鄧安福;;剛性下臥層對上部土層變形的影響[J];巖土工程技術(shù);2005年06期

7 丁利;;考慮軟土結(jié)構(gòu)性的砂井地基下臥層固結(jié)性狀的計(jì)算與分析[J];廣東土木與建筑;2008年02期

8 亓樂;;剛性樁復(fù)合地基下臥層沉降計(jì)算[J];河海大學(xué)學(xué)報(bào)(自然科學(xué)版);2009年02期

9 湯梅芳;楊龍才;王炳龍;;懸浮樁復(fù)合地基下臥層沉降計(jì)算的對比分析[J];路基工程;2005年06期

10 馬靜;徐亞利;郭濤;;地震波荷載下持力層與下臥層對樁的影響[J];科技信息(科學(xué)教研);2007年20期

相關(guān)會議論文 前2條

1 亓樂;王青松;劉薇;;復(fù)合地基樁端向下臥層刺入量計(jì)算方法[A];第3屆全國工程安全與防護(hù)學(xué)術(shù)會議論文集[C];2012年

2 韓相超;孟永會;呂遠(yuǎn)強(qiáng);;對旋噴樁加固高層住宅樓地基下臥層的可行性分析——以西安市長安區(qū)某高層住宅樓地基為例[A];第九屆全國工程地質(zhì)大會論文集[C];2012年

相關(guān)重要報(bào)紙文章 前1條

1 ;東線山東段工程簡介[N];中國水利報(bào);2003年

相關(guān)碩士學(xué)位論文 前1條

1 李紅星;傾斜卵石下臥層對基礎(chǔ)及上部結(jié)構(gòu)的影響[D];西安建筑科技大學(xué);2010年

，

本文編號：2354801