【摘要】：山區(qū)河道城市化前溪流深切,城市化后天然河流與周邊地塊存在較大高差,設(shè)計(jì)從防洪、水生態(tài)等多目標(biāo)出發(fā),提出了適應(yīng)山區(qū)城市的雙層河道建設(shè)方案:上層明渠、下層暗涵。其中,下層暗涵河道在場(chǎng)平過程中深埋地下,維護(hù)、檢修困難且事故后果嚴(yán)重,因此對(duì)其結(jié)構(gòu)受力特性的掌握尤為重要,在設(shè)計(jì)階段加以考量能有效降低其事故風(fēng)險(xiǎn)。回填場(chǎng)區(qū)的地形、滲透特性使得強(qiáng)降雨條件下涵周土體內(nèi)地下水環(huán)境會(huì)發(fā)生劇烈變化,土體若長(zhǎng)時(shí)間呈沁水飽和狀態(tài),對(duì)場(chǎng)區(qū)的構(gòu)筑物極為不利,因此考慮將外水通過涵體透水通道導(dǎo)入下層河道向下游排出,此時(shí)結(jié)構(gòu)將會(huì)遭遇地下水水位變化這一工況。現(xiàn)行規(guī)范通過載荷—結(jié)構(gòu)方式計(jì)算水荷載時(shí)通常進(jìn)行折減或采用可能的最大水位,而涵體受力實(shí)質(zhì)是與滲流—應(yīng)力雙場(chǎng)耦合作用下的涵周土體共同變形的過程,因此,研究深埋地下框架結(jié)構(gòu)在地下水位變化所產(chǎn)生的流固耦合效應(yīng)作用下的受力特性具有重要的工程應(yīng)用價(jià)值。本文依托工程實(shí)例建立了地下框架結(jié)構(gòu)三維有限元模型,主要研究?jī)?nèi)容如下:(1)從基本理論有效應(yīng)力原理和達(dá)西定律出發(fā),推導(dǎo)了應(yīng)力場(chǎng)、滲流場(chǎng)的控制方程:應(yīng)力平衡方程和非穩(wěn)定飽和滲流連續(xù)方程,并給出相應(yīng)的定解條件。根據(jù)兩場(chǎng)相互作用的的影響方式,得到了多孔介質(zhì)土體滲流場(chǎng)應(yīng)力場(chǎng)耦合的數(shù)學(xué)模型并給出了耦合狀態(tài)下的有限元矩陣格式和求解方式。闡述了三維有限元模型建立過程中的要點(diǎn),并依托實(shí)例工程地勘報(bào)告和相應(yīng)土工實(shí)驗(yàn)成果給出模型參數(shù)。(2)模擬分層回填施工過程,其涵頂存在應(yīng)力集中現(xiàn)象,此為深埋框架結(jié)構(gòu)所特有的受荷形式;模擬水位下降固結(jié)過程,其有效應(yīng)力的增長(zhǎng)由產(chǎn)生明顯水位降前(主要)、明顯水位降落過程、涵側(cè)水位降落過程三階段階段的孔壓溢出、沉降差(35)h產(chǎn)生的應(yīng)力集中共同貢獻(xiàn),此時(shí)水位降幅快慢并不適用來(lái)衡量?jī)?nèi)力變化的趨勢(shì)。固結(jié)排水過程使得沉降加劇、內(nèi)力增大,結(jié)構(gòu)受荷破壞的風(fēng)險(xiǎn)相應(yīng)增大。(3)回填材料對(duì)涵體受荷以及內(nèi)力響應(yīng)影響較大的因子為彈性模量E以及滲透系數(shù)k,不考慮涵背回填、涵側(cè)排水工程措施時(shí),僅存在土石混合料的單參數(shù)作用下,場(chǎng)區(qū)回填料彈性模量E_m越大、滲透量級(jí)較高時(shí)滲透系數(shù)K_m相對(duì)越小結(jié)構(gòu)越有利;反之,引入涵背砂礫石回填料,其彈性模量E_s、滲透系數(shù)k_s,在多參數(shù)作用下,E_m越小、E_s越大、K_m大于并接近k_s、k_s越小時(shí),對(duì)結(jié)構(gòu)越有利,其中,在相同的變化量級(jí)范圍內(nèi),E_m比E_s更敏感,k_s比K_m更敏感�？傮w來(lái)說,在涵側(cè)土體范圍內(nèi)采用相應(yīng)工程措施能有效減小結(jié)構(gòu)受荷及內(nèi)力大小,且更為經(jīng)濟(jì)高效。
[Abstract]:Before the urbanization of mountain rivers, the rivers are deep, and there is a great difference in height between the natural rivers and the surrounding land blocks after urbanization. From the multi-objectives of flood control and water ecology, this paper puts forward the construction scheme of the double-layer river channels suitable for mountain cities: the upper open canal, the open channel in the upper layer, and so on. The lower culvert. Among them, the underground is buried deeply in the course of the hidden culvert in the course of site leveling, the maintenance is difficult and the accident consequence is serious. Therefore, it is very important to master the mechanical characteristics of the structure, and the risk of the accident can be effectively reduced by considering it in the design stage. The topography and permeation characteristics of backfill site make the groundwater environment of culvert surrounding soil change dramatically under heavy rainfall. If the soil is saturated with water for a long time, it will be very unfavorable to the structure of the field area. Therefore, it is considered that the external water will be discharged from the lower river through the culvert permeable channel, and the structure will be subjected to the condition of groundwater level variation at this time. In the current code, the maximum water level is usually reduced or the maximum water level is adopted when calculating the water load by load-structure method, and the stress of culvert is essentially the process of deformation of soil around culvert under the coupling of seepage and stress, so, It has important engineering application value to study the mechanical characteristics of deep buried underground frame structure under the effect of fluid-solid coupling caused by the change of groundwater level. In this paper, a three-dimensional finite element model of underground frame structure is established on the basis of engineering examples. The main research contents are as follows: (1) the stress field is derived from the basic theory of effective stress principle and Darcy's law. The governing equations of seepage field are stress balance equation and unsteady saturated seepage continuity equation, and the corresponding definite solution conditions are given. According to the influence mode of the interaction of two fields, the mathematical model of the coupling of seepage field and stress field in porous media is obtained, and the finite element matrix format and the solution method under the coupling state are given. The main points in the process of establishing 3D finite element model are expounded, and the model parameters are given based on the geological prospecting report of practical engineering and the corresponding geotechnical experiment results. (2) the stress concentration phenomenon exists in the culvert top of the culvert when the construction process of layered backfill is simulated. This is the special loading form of the deep buried frame structure, and the increase of effective stress is caused by the pore pressure overflow in the three stages of the water level descending process, the obvious water level falling process and the culvert side water level falling process, and the increase of the effective stress in the simulated water level descending consolidation process is mainly caused by the obvious water level drop (mainly). The stress concentration caused by the settlement difference (35) h contributes together, and the water level decline is not suitable to measure the trend of internal force change at this time. During consolidation and drainage process, settlement intensifies, internal force increases, and the risk of structural damage under loading increases accordingly. (3) the factors which have a great influence on the response of culvert and internal force are elastic modulus E and permeability coefficient k, and the backfill is not considered. In culvert drainage engineering measures, under the action of only one parameter of earth-rock mixture, the larger the elastic modulus E _ m of backfill in field area is, the more favorable is the structure of permeability coefficient km _ m when the order of permeability is higher; The smaller the ESM is, the bigger the KSM is, the smaller it is and the smaller it is, the smaller the structure is, the more favorable the structure is to the structure. In the same range of variations, Em is more sensitive than ES, and KS is more sensitive than KM. In general, using the corresponding engineering measures in the range of the culvert soil can effectively reduce the load and internal force of the structure, and it is more economical and efficient.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TV31

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 黃宏偉;劉印;張冬梅;;盾構(gòu)隧道長(zhǎng)期滲水對(duì)地表沉降及管片內(nèi)力的影響[J];中國(guó)鐵道科學(xué);2012年06期

2 徐日慶;張慶賀;劉鑫;廖斌;;考慮滲透性的水-土壓力計(jì)算方法[J];巖土工程學(xué)報(bào);2012年05期

3 王洪新;;水土壓力統(tǒng)一計(jì)算理論的證明及水土共同作用下的壓力計(jì)算[J];巖石力學(xué)與工程學(xué)報(bào);2012年02期

4 陳保國(guó);孫金山;張磊;;上埋式鋼筋混凝土拱涵受力特性及地基處理研究[J];巖土力學(xué);2011年05期

5 李宗坤;陳麗剛;韓立煒;;基于ABAQUS滲流與應(yīng)力耦合的邊坡穩(wěn)定性分析[J];人民黃河;2011年02期

6 羅富榮;劉峧煒;韓煊;;地下水水位上升對(duì)地鐵隧道結(jié)構(gòu)的影響分析[J];中國(guó)鐵道科學(xué);2011年01期

7 許金華;何川;夏煒洋;;水下盾構(gòu)隧道滲流場(chǎng)應(yīng)力場(chǎng)耦合效應(yīng)研究[J];巖土力學(xué);2009年11期

8 鄭俊杰;趙建斌;陳保國(guó);;高路堤下涵洞垂直土壓力研究[J];巖土工程學(xué)報(bào);2009年07期

9 彭文春;;地下水對(duì)隧道受力變形影響的計(jì)算分析[J];中國(guó)新技術(shù)新產(chǎn)品;2009年06期

10 鄭俊杰;陳保國(guó);張世飆;;溝埋式涵洞非線性土壓力試驗(yàn)研究與數(shù)值模擬[J];巖土工程學(xué)報(bào);2008年12期

相關(guān)碩士學(xué)位論文 前1條

1 劉德華;不同地下水位環(huán)境下地鐵隧道結(jié)構(gòu)的劣化機(jī)制研究[D];北京建筑大學(xué);2015年

，

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