本文選題：支護設計　切入點：鋼管樁　出處：《中國礦業(yè)大學》2017年碩士論文

【摘要】：本文以北京某基坑1-1支護剖面為原型通過理論設計、模型試驗、數(shù)值模擬研究了鋼管樁基坑支護的位移、應力、變形及對基坑穩(wěn)定性的影響,對鋼管樁代替鉆孔灌注樁的可行性進行了研究。通過理論計算設計了6種不同直徑、壁厚的鋼管樁代替鉆孔灌注樁進行基坑支護。選用了最大、最小直徑的兩種鋼管樁進行了物理模型試驗,試驗結果表明大直徑管樁單根樁打樁引起的土體水平位移、豎向位移以及作用范圍均較大,但在相同支護區(qū)域內土體水平位移的累積位移值差別不大。應力監(jiān)測表明,打樁引起的土體應力變化主要在樁體的下部分,小直徑管樁施工造成的土體應力增幅大于大直徑管樁。對錘擊數(shù)的分析表明隨著管入土深度的增加大,將大直徑管樁打入土體的錘擊數(shù)增幅大于小直徑管樁,但小直徑管樁的擠土效應更明顯。基坑開挖模擬表明土體的水平位移變化在基坑邊緣處最大,大、小兩種管樁開挖引起的水平位移開挖模擬值分別為3.23 mm、10.16 mm,現(xiàn)場實測值中最大值約為4 mm。小直徑管樁在開挖后期模型箱邊緣土體有小部分垮落,大直徑的管樁開挖過程中出現(xiàn)了土體的大范圍垮落。小直徑管樁保持樁后土體的整體性較好,但控制水平位移的能力較差,而大直徑管樁在支護時更需要與其他支護結構結合使用。相似模擬的土體沉降趨勢與實測沉降值相似,大、小兩種管樁支護情況下的最終沉降值分別為-2 mm、-3.48 mm,實測最大值為-2.04 mm,根據(jù)模擬值與實測值可將土體的沉降變化分為3個階段:沉降發(fā)展階段、沉降過渡階段以及沉降穩(wěn)定階段,模型試驗中沉降過渡階持續(xù)時間短。數(shù)值模擬表明,隨著鋼管樁直徑的增大,樁體的剛度增大,樁后土體的位移、管樁承受的應力水平均變小,但鋼管樁直徑對基底隆起并無影響。樁后土體位移的數(shù)值模擬值、模型試驗值、實測值均小于監(jiān)測報警值,樁身的應力均遠小于鋼材的強度設計值,表明所設計的鋼管樁滿足控制土體位移的要求且鋼管樁自身安全穩(wěn)定。以直徑1.0 m的鋼管樁為例,分析了布置間距對基坑的影響,建議在實際工程中采用2.0D間距布置鋼管樁。
[Abstract]:In this paper, the displacement, stress, deformation and the influence on the stability of a steel pipe pile foundation pit are studied by theoretical design, model test and numerical simulation based on the 1-1 supporting section of a foundation pit in Beijing.The feasibility of replacing bored pile with steel pipe pile is studied.Through theoretical calculation, six kinds of steel pipe piles with different diameters and wall thickness are designed to support foundation pit instead of bored piles.Two kinds of steel pipe piles with maximum and minimum diameters are selected for physical model test. The results show that the horizontal displacement, vertical displacement and action range of soil caused by single pile of large diameter pipe pile are large.However, the cumulative displacement of soil in the same supporting area is not different.Stress monitoring shows that the stress variation of soil caused by piling is mainly in the lower part of the pile, and the increase of soil stress caused by the construction of small diameter pipe pile is larger than that of large diameter pipe pile.The analysis of hammer number shows that with the increase of pipe depth, the increase of hammer hit number of large diameter pipe pile is larger than that of small diameter pipe pile, but the squeezing effect of small diameter pipe pile is more obvious.The simulation of excavation shows that the horizontal displacement of soil is the largest at the edge of the foundation pit, and the simulated values of the horizontal displacement caused by the excavation of two kinds of pipe piles are 3.23 mm and 10.16 mm, respectively, and the maximum value of the field measured value is about 4 mm.In the later stage of excavation, a small part of soil collapse occurred at the edge of the model box, and a large scale collapse occurred during the excavation of the large-diameter pipe pile.The small diameter pipe pile keeps the integrity of the soil after the pile, but the ability to control horizontal displacement is poor, while the large diameter pipe pile needs to be used in combination with other supporting structures.The settlement trend of similar simulated soil is similar to the measured settlement value.The final settlement values of the two types of pipe piles are 2.mm -3.48 mm and the measured maximum value is -2.04 mm. According to the simulated values and the measured values, the settlement changes of soil can be divided into three stages: the stage of settlement development, the stage of settlement transition and the stage of settlement stabilization.In the model test, the duration of settlement transition order is short.Numerical simulation shows that with the increase of the diameter of the steel pipe pile, the stiffness of the pile body increases, the displacement of the soil behind the pile and the stress level of the pipe pile become smaller, but the diameter of the steel tube pile has no effect on the uplift of the foundation.The numerical simulation values, model test values and measured values of the soil displacement behind the pile are all smaller than the monitoring alarm values, and the stress of the pile body is far less than the strength design value of the steel.The results show that the designed steel pipe pile can meet the requirement of controlling the displacement of soil and the steel pipe pile itself is safe and stable.Taking the steel pipe pile with diameter of 1.0 m as an example, the influence of layout spacing on foundation pit is analyzed, and it is suggested that the steel pipe pile should be arranged with 2.0D spacing in practical engineering.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU473.1

【參考文獻】

相關期刊論文 前10條

1 胡欣;;模型試驗模擬不同工況下基坑開挖對既有隧道的影響[J];路基工程;2015年06期

2 孟長江;;福州站北廣場深基坑工程實例分析[J];鐵道工程學報;2015年10期

3 黃雪峰;陳帥強;馬龍;;懸臂式支護樁內力分布規(guī)律試驗研究[J];四川建筑科學研究;2015年01期

4 翟玉新;;鋼管樁與灌注樁結合支護方式應用探索[J];鐵道建筑技術;2013年11期

5 陳立宏;袁希雨;;砂土中旋挖擠擴灌注樁的抗拔模型實驗[J];北京交通大學學報;2013年04期

6 李華;;盾構開挖區(qū)錨桿(索)快速清除施工技術[J];現(xiàn)代城市軌道交通;2012年06期

7 楊震偉;;基坑工程開挖支護的數(shù)值計算分析[J];鐵道建筑;2012年05期

8 雷華陽;李肖;陸培毅;霍海峰;;管樁擠土效應的現(xiàn)場試驗和數(shù)值模擬[J];巖土力學;2012年04期

9 王旭軍;;上海中心大廈裙房深大基坑工程圍護墻變形分析[J];巖石力學與工程學報;2012年02期

10 李兆平;黃明利;王建;李文濤;;地鐵深基坑采用可回收錨索支護方案優(yōu)化設計[J];地下空間與工程學報;2012年01期

相關博士學位論文 前4條

1 樊向陽;靜壓樁施工沉樁阻力及沉樁擠土效應研究[D];同濟大學;2007年

2 劉燕;地鐵換乘樞紐后建車站施工影響研究[D];同濟大學;2007年

3 王建軍;基坑支護現(xiàn)場試驗研究與數(shù)值分析[D];中國建筑科學研究院;2006年

4 俞曉;深基坑開挖與支護的模型試驗與ANSYS分析研究[D];武漢理工大學;2005年

相關碩士學位論文 前10條

1 賈景松;鋼管樁在攪拌樁復合土釘墻支護體系中的應用研究[D];華南理工大學;2015年

2 李瑩;北京市某深基坑工程剛性微型樁支護結構研究[D];中國地質大學（北京）;2014年

3 劉暢;中國大陸地鐵報探析[D];湖南大學;2014年

4 劉攀;成都地區(qū)排樁支護結構土壓力研究[D];西南交通大學;2014年

5 梁健;合肥某地鐵站深基坑樁錨聯(lián)合支護數(shù)值模擬與現(xiàn)場監(jiān)測[D];安徽建筑大學;2014年

6 林敏博;大直徑超長鋼管樁的土塞效應研究[D];天津大學;2014年

7 周小龍;青島地鐵土巖結合基坑支護中微型鋼管樁的試驗研究[D];青島理工大學;2013年

8 劉妮;基于原型樁基的鋼管樁壓—彎—剪荷載下受力特性的分析研究[D];西南交通大學;2013年

9 趙雙益;超長鉆孔灌注樁單樁豎向承載性能研究[D];中南大學;2013年

10 晉霞;深基坑開挖與鄰建基礎相互影響模型試驗研究[D];蘭州交通大學;2013年

，

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