鄰近開挖對橋梁樁基變形與內(nèi)力影響分析
發(fā)布時間：2018-07-24 08:20
【摘要】：研究目的:鄰近開挖會對橋梁樁基造成不利影響,嚴(yán)重時將影響高速鐵路的運(yùn)營品質(zhì)與安全。本文通過現(xiàn)場原型試驗,獲得深厚軟土地區(qū)3種開挖工況下鄰近樁基的工作性狀,采用ABAQUS有限元軟件對試驗過程進(jìn)行三維數(shù)值模擬,通過與試驗結(jié)果的對比分析,驗證計算模型與參數(shù)的合理性�；隍炞C后的計算模型,探討無支護(hù)開挖主要參數(shù)(基坑寬度、邊緣凈距、基坑深度)對樁身變形與內(nèi)力的影響規(guī)律。研究結(jié)論:(1)鄰近開挖引起的樁身位移與彎矩分布范圍約為設(shè)計時主動受力樁的2.1~2.8倍,劣化了樁基的工作狀態(tài),在高速鐵路運(yùn)營維護(hù)中應(yīng)引起高度重視;(2)基坑寬度大于5倍的邊緣凈距時,可忽略繼續(xù)向外側(cè)加寬基坑對鄰近樁基的影響;(3)當(dāng)邊緣凈距大于30 m(相當(dāng)于6倍的基坑寬度)時,開挖窄淺基坑(寬度≤5 m且深度≤3 m)對鄰近樁基的影響不大;(4)樁頂水平位移、樁身最大彎矩隨深寬比增加大致呈指數(shù)型增長趨勢,且間距越小,其增長速率越大;(5)本研究成果可供高鐵橋梁樁基設(shè)計、施工、運(yùn)營維護(hù)借鑒。
[Abstract]:Research purpose: the adjacent excavation will have adverse effects on the bridge pile foundation, and will affect the operation quality and safety of the high-speed railway seriously. In this paper, through the field prototype test, the working characteristics of adjacent pile foundation under three excavation conditions in deep soft soil region are obtained. The three-dimensional numerical simulation of the test process is carried out by using ABAQUS finite element software, and the results are compared with the test results. The rationality of the calculation model and parameters is verified. Based on the verified calculation model, the influence of main parameters (width, margin, depth) of unsupported excavation on the deformation and internal force of pile is discussed. The conclusions are as follows: (1) the distribution range of displacement and bending moment of pile caused by adjacent excavation is about 2.1or 2.8 times as much as that of active force pile in design, which results in the deterioration of the working state of pile foundation. High attention should be paid to the operation and maintenance of high-speed railway; (2) when the width of foundation pit is larger than 5 times of the margin net distance, the influence of widening the foundation pit to the adjacent pile foundation can be neglected; (3) when the margin net distance is greater than 30 m (equivalent to 6 times the width of foundation pit), The excavation of narrow and shallow foundation pit (width 鈮，
本文編號：2140788
[Abstract]:Research purpose: the adjacent excavation will have adverse effects on the bridge pile foundation, and will affect the operation quality and safety of the high-speed railway seriously. In this paper, through the field prototype test, the working characteristics of adjacent pile foundation under three excavation conditions in deep soft soil region are obtained. The three-dimensional numerical simulation of the test process is carried out by using ABAQUS finite element software, and the results are compared with the test results. The rationality of the calculation model and parameters is verified. Based on the verified calculation model, the influence of main parameters (width, margin, depth) of unsupported excavation on the deformation and internal force of pile is discussed. The conclusions are as follows: (1) the distribution range of displacement and bending moment of pile caused by adjacent excavation is about 2.1or 2.8 times as much as that of active force pile in design, which results in the deterioration of the working state of pile foundation. High attention should be paid to the operation and maintenance of high-speed railway; (2) when the width of foundation pit is larger than 5 times of the margin net distance, the influence of widening the foundation pit to the adjacent pile foundation can be neglected; (3) when the margin net distance is greater than 30 m (equivalent to 6 times the width of foundation pit), The excavation of narrow and shallow foundation pit (width 鈮，
本文編號：2140788
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