本文關(guān)鍵詞：采煤沉陷區(qū)框架橋旁側(cè)堆載地基加固機(jī)理研究　出處：《中國礦業(yè)大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 采煤沉陷區(qū) 旁側(cè)堆載 地基承載力 數(shù)值計算 理論推導(dǎo) 復(fù)合雙層地基

【摘要】：淮南礦業(yè)集團(tuán)謝橋煤礦濟(jì)河鐵路中橋，受煤層群開采的影響，橋基地表沉陷量巨大，僅豎直方向的沉陷已超過10m。由于橋梁上部結(jié)構(gòu)加高，地基承載力不滿足要求，，該橋已經(jīng)進(jìn)行過一次高壓旋噴樁地基處理，常規(guī)既有建（構(gòu)）筑物地基加固方法很難再次適用。在這種背景下本文提出將旁側(cè)堆載加固方法應(yīng)用到采煤沉陷區(qū)橋梁地基的加固治理中，開展了天然地基和既有復(fù)合地基旁側(cè)堆載加固機(jī)理研究。以FLAC3D數(shù)值計算和假定滑移面法理論分析為研究手段，分析了堆載參數(shù)對地基極限承載力的影響規(guī)律，給出了地表超載和地基承載力增量的近似關(guān)系式；通過理論推導(dǎo)，給出地基承載力增量計算公式，為采煤沉陷區(qū)橋梁地基堆載設(shè)計提供一定理論基礎(chǔ)。 本文首先通過數(shù)值模型試驗，分析了天然地基和既有復(fù)合地基堆載加固時地基承載力變化規(guī)律。通過改變天然地基煤矸石堆載體尺寸及位置參數(shù)，經(jīng)分析得出高度是影響加固效果的主要因素的結(jié)論。在堆載高度H1≤6m時，高度與地基承載力增量近似為線性關(guān)系；通過改變堆載體物理力學(xué)參數(shù)，經(jīng)分析得出填料容重是影響加固效果的主要因素的結(jié)論，容重與地基承載力增量近似為線性關(guān)系。根據(jù)天然地基研究成果，在既有復(fù)合地基堆載法的研究中，僅考慮了堆載高度和填料容重兩個可變因素，得到地表堆載量與地基承載力提升幅度之間的近似關(guān)系式。 其次采用假定滑移面法，對天然地基和既有復(fù)合地基，在考慮堆載情況下地基承載力增量進(jìn)行理論推導(dǎo)，并與數(shù)值計算成果對比，分析差異。對于采煤沉陷區(qū)天然地基堆載后地基承載力增量Δf a的確定可參照《建筑地基基礎(chǔ)設(shè)計規(guī)范》，考慮采動影響，地基土物理力學(xué)參數(shù)取采動后的降低值，得到的堆載后地基承載力特征值增量Δf a計算公式，式中堆載極限高度H1=6m；本文根據(jù)復(fù)合雙層地基理論，推導(dǎo)地表超載作用下地基極限承載力增量Δp a的基本表達(dá)式，式中堆載極限高度H1=6m，考慮采動影響，地基土物理力學(xué)參數(shù)取采動后的降低值。 最后根據(jù)上述研究成果，將旁側(cè)堆載法應(yīng)用于淮南礦區(qū)濟(jì)河橋加固設(shè)計中。堆載后加固區(qū)地基承載力提升近5.4%，而下臥層地基承載力提升約14.9%，堆載法將應(yīng)用于淮南礦區(qū)地基處理。
[Abstract]:Huainan Mining Group Corporation Ltd Ji river railway bridge, affected by coal mining, surface subsidence huge bridge base, only vertical subsidence has been more than 10m. because of the upper structure of the bridge height, does not meet the requirements of the bearing capacity of the foundation, the bridge has been a high pressure jet grouting pile foundation treatment, the conventional building is (structure) building foundation reinforcement method is difficult to apply again. In this context this paper will reinforce the governance side loading reinforcement method applied to coal mining subsidence area of bridge foundation, the natural foundation and the both side pile composite foundation load calculation and reinforcement mechanism study. Analysis of slip surface method assumes that the theory research method with FLAC3D values, analyze the influence law of loading parameters on ultimate bearing capacity of foundation, gives the ground overload and bearing the approximate relation of stress increment; through theoretical derivation, increase the bearing capacity of foundation are given The calculation formula provides a theoretical basis for the load design of the bridge foundation in the coal mining subsidence area.
Firstly, the numerical model tests, analysis of the existing natural foundation and foundation bearing capacity variation of composite foundation pile load reinforcement. By changing the natural foundation of the coal gangue carrier size and position parameters obtained by the analysis are the main factors that influence the height of the strengthening effect of knot theory. In the stacking height of H1 = 6m, height with the increment of bearing capacity is approximately linear; by changing the physical and mechanical parameters of pile carrier, through the analysis of filler bulk density is the main factor affecting the reinforcement effect of the conclusion, approximately linear relation between the bearing capacity of foundation. According to the increment of density and natural foundation in the existing research results, the composite foundation pile load research method, considering only the the stacking height and packing density of two variable factors, get the surface load and pile foundation bearing capacity to enhance the approximate relation between the amplitude.
Secondly it is assumed that the sliding surface method is used for both natural foundation and composite foundation, considering the loading condition of foundation bearing capacity increment theory, and the numerical calculation results, analysis of the differences. For the pile bearing capacity increment f a can refer to < code of building foundation design foundation on natural area > the foundation of coal mining subsidence, mining influence, foundation soil physical parameters to decrease the dynamic value of value increment f a formula to calculate the bearing capacity of the pile foundation load characteristics, type loading height limit of H1=6m; according to the theory of compound two-layer foundation, bearing a basic expression force increment P limit ground surface is under overload, load limit height of H1=6m pile type, mining influence, foundation soil physical parameters to decrease the value after the move.
Based on the above results, the loading method is applied to the side of Huainan mining area economy river bridge design. After loading reinforcement foundation bearing capacity of nearly 5.4%, while the underlying layer of foundation bearing capacity increases about 14.9%, loading method applied in Huainan mining area ground treatment.

【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U443.17;U448.14

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