發(fā)布時間：2019-05-19 08:03

【摘要】：隨著國民生產(chǎn)水平快速增長,機場的建設(shè)及擴建也進入了井噴時代,山區(qū)的高填方工程越來越多。場區(qū)地形高低起伏,土石挖填方工程量大,且水文地質(zhì)條件較復雜,水位隨季節(jié)變化明顯,在降雨或者地下水滲流過程中,填料的浸濕會引起濕化沉降。如何準確評價填方體在濕化條件下的沉降及差異沉降規(guī)律,使高填方體在施工期和工后的沉降及差異沉降滿足工程要求是非常重要的問題。本文通過現(xiàn)場試驗和對工程現(xiàn)場的長期分層沉降監(jiān)測,結(jié)合FLAC3D數(shù)值模擬,研究了濕化條件下高填方體的沉降及差異沉降相比天然工況下的增大程度。主要的研究內(nèi)容和研究成果如下:①分析了土石混合填料的濕化變形機理及影響因素。通過現(xiàn)場單環(huán)注水試驗,得到研究區(qū)填方體的滲透系數(shù);通過現(xiàn)場探槽開挖試驗,得到填土體的含水率沿剖面縱向的變化規(guī)律。再利用經(jīng)驗公式計算得出該研究區(qū)降雨入滲的影響深度。②通過對填方體的分層沉降監(jiān)測,施工加載期的最大沉降量為43.09cm,沉降速率為0.71~2.56mm/d,加載結(jié)束后的沉降速率為0.13~0.32mm/d。沉降速率及沉降量與填方體高度、施工填筑速率成正相關(guān),含水率隨土體深度變化的表達式為y=-0.0484x2-0.1781x+10.468,當含水率增大時,沉降速率也有一定的增大。③利用Auto CAD—ANSYS—FLAC3D三者結(jié)合建立復雜地形下的三維數(shù)值模型。X和Y方向位移較大部位均發(fā)生在邊坡處,邊坡坡度越大,位移值越大。Z向的沉降主要取決于填方體的高度,在最高填方高度29.8m處的最大沉降值為52.93cm。最大差異沉降率和平均差異沉降率分別為11.42‰和3.41‰。濕化條件下選取了三種工況:降雨入滲濕化影響深度分別為5m、10m、20m,對應的地下水位上升1m、3m、5m,得到最大沉降變形相比天然工況下增大比例分別為3.5%、12%和20%左右,且濕化深度的增加對填方體沉降的影響要比地下水位上升產(chǎn)生的影響大。將其與實際監(jiān)測結(jié)果對比發(fā)現(xiàn)與工程的實際情況較為吻合。④基于多因素正交極差分析原理,對影響填方體沉降的參數(shù)敏感性進行了分析,得到敏感性順序為:變形模量E0密度?粘聚力c內(nèi)摩擦角?泊松比μ。基于已有的監(jiān)測數(shù)據(jù),對巖土體力學參數(shù)進行反演研究,并將反演得到的參數(shù)代入模型對其余監(jiān)測點進行計算,結(jié)果表明反演得到的參數(shù)是比較合理的。
[Abstract]:With the rapid growth of national production level, the construction and expansion of airport has entered the era of blowout, and there are more and more high fill projects in mountainous areas. The topography of the field area is undulating, the quantity of earth-rock excavation and filling is large, and the hydrogeological conditions are complex, and the water level varies obviously with the season. in the process of rainfall or groundwater seepage, the wetting of the packing will cause humidification settlement. How to accurately evaluate the settlement and differential settlement of the fill under the condition of humidification, so that the settlement and differential settlement of the high fill during and after construction meet the engineering requirements is a very important problem. In this paper, the settlement and differential settlement of high fill under humidification condition are studied by field test and monitoring of long-term layered settlement in engineering site, combined with FLAC3D numerical simulation. The main research contents and results are as follows: 1. The humidification deformation mechanism and influencing factors of soil-rock mixed fillers are analyzed. Through the field single ring water injection test, the permeability coefficient of the fill body in the study area is obtained, and the variation law of the moisture content of the filled soil along the longitudinal direction of the section is obtained through the field grooving excavation test. The influence depth of rainfall infiltration in the study area is calculated by using the empirical formula. 2 through the layered settlement monitoring of the fill, the maximum settlement of the construction loading period is 43.09 cm, and the settlement rate is 0.71 鈮，

本文編號：2480544