本文選題：軟土 + 樁基礎(chǔ)　； 參考：《西南交通大學(xué)》2014年碩士論文

【摘要】：由于軟土具有低強(qiáng)度、高壓縮性的特點,在軟土地區(qū)修建高鐵一般選用樁基礎(chǔ),但水平荷載下樁基礎(chǔ)的承載性能是一個非常復(fù)雜的樁土相互作用過程。同時,規(guī)范中的m法受眾多因素影響,對軟土地區(qū)橫向受荷樁基礎(chǔ)進(jìn)行設(shè)計并不能達(dá)到預(yù)期的效果,存在一定的優(yōu)化空間。因此本論文針對以上不足綜合考慮,采用ABAQUS數(shù)值分析手段分別對影響單樁、群樁基礎(chǔ)水平承載性能的主要因素進(jìn)行分析,對比其水平受力特性規(guī)律,包括樁長、樁徑、樁間距等,并通過m值反演和數(shù)理統(tǒng)計分析,得到如下主要結(jié)論： 1.無論是單樁還是群樁基礎(chǔ),樁身水平位移和樁身彎矩都隨水平荷載的增大而增大；對于群樁基礎(chǔ),各排樁樁身水平位移隨水平力的變化基本一致,前排樁最大彎矩大于中、后樁的最大彎矩,中、后排樁的最大彎矩基本相同。 2.無論是單樁還是群樁基礎(chǔ),樁身剛度對樁身水平位移、樁身彎矩和各排樁的樁身最大彎矩分擔(dān)比例均影響較小。 3.無論是單樁還是群樁基礎(chǔ),樁徑增大,樁身水平位移減小,同時樁身彎矩增大：對于群樁基礎(chǔ),增大樁徑,中、后排樁的樁身最大彎矩分擔(dān)比例有所提高。 4.無論是單樁還是群樁基礎(chǔ),樁長增大對樁身水平位移和樁身彎矩均影響很小；對于群樁基礎(chǔ),樁長增大,中、后排樁的樁身最大彎矩分擔(dān)比例有所提高。 5.群樁基礎(chǔ)中,縱向樁間距增大,樁身水平位移明顯減小,同時樁身最大彎矩減小,且中、后排樁的樁身最大彎矩分擔(dān)比例降低較多,平均降低了13%；橫向樁間距增大,樁身水平位移減小,樁身最大彎矩增大,中、后排樁的樁身最大彎矩分擔(dān)比例有所降低,分別降低了2%和9%。 6.群樁基礎(chǔ)中,針對滬通高鐵工程三個典型軟土地層,中排樁樁身最大彎矩占前排樁樁身最大彎矩的比例為65%～74%；后排樁樁身最大彎矩占前排樁樁身最大彎矩的比例為55%-73%。 7.對m值進(jìn)行反演分析和統(tǒng)計分析,得到該地區(qū)更精確的m值范圍以及m與主要影響參數(shù)之間的關(guān)系式。
[Abstract]:Because the soft soil has the characteristics of low strength and high pressure shrinkage, the pile foundation is generally chosen in the soft soil area, but the bearing capacity of the pile foundation under the horizontal load is a very complicated process of pile soil interaction. At the same time, the m method in the standard is influenced by many factors, and the design of the lateral bearing pile foundation in the soft soil area can't be achieved. In this paper, the main factors affecting the horizontal bearing performance of single pile and pile foundation are analyzed with ABAQUS numerical analysis method, and the horizontal loading characteristics are compared, including pile length, pile diameter and pile spacing, and the m value inversion and mathematical statistics are used. The main conclusions are as follows:
1. both the single pile and the group pile foundation, the horizontal displacement and the pile bending moment of the pile increase with the increase of the horizontal load; for the group pile foundation, the horizontal displacement of each pile pile body is basically consistent with the horizontal force, the maximum bending moment of the front pile is greater than that in the middle, the maximum bending moment of the post pile, the maximum bending moment of the back row pile is basically the same.
2. whether it is single pile or group pile foundation, pile stiffness has little effect on the horizontal displacement of pile, the moment of pile and the maximum moment share of piles.
3. whether single pile or group pile foundation, pile diameter increases, pile body horizontal displacement decreases, and pile body bending moment increases. For group pile foundation, increasing pile diameter, and the maximum bending moment sharing ratio of pile body in back row pile increases.
4. no matter the single pile or the group pile foundation, the pile length increase has little influence on the horizontal displacement of the pile body and the pile body bending moment. For the group pile foundation, the pile length increases, and the maximum bending moment sharing ratio of the pile body in the back row pile increases.
In the 5. group pile foundation, the vertical pile spacing increases, the horizontal displacement of pile body decreases obviously, and the maximum bending moment of pile body decreases. In addition, the proportion of maximum bending moment of pile body in back row pile is reduced more, the average decrease of 13%, the horizontal displacement of pile body and the maximum bending moment of pile body increase, and the maximum bending moment of pile body is shared in the back row pile. The ratio is reduced by 2% and 9%., respectively.
In the 6. group pile foundation, according to the three typical soft soil strata of Hutong high speed rail project, the maximum bending moment of the middle row pile pile body is 65% ~ 74%, the maximum bending moment of the rear pile pile body is 55%-73%.
7. inverse analysis and statistical analysis of the m value, get the more accurate m range in this area and the relationship between M and main influence parameters.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U443.15

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本文編號：1987513