本文選題：箱形渡槽 + 冬季輸水��； 參考：《蘭州交通大學(xué)》2014年碩士論文

【摘要】：我國水資源時空分布不均且人均水量不足，這導(dǎo)致我國部分地區(qū)水資源嚴(yán)重短缺。為了解決我國水資源分布不均勻與供水需求不完全適應(yīng)的問題，我國修建了一系列跨地區(qū)、跨流域、長距離的水資源調(diào)配工程。在這些大型輸水工程中，渡槽是應(yīng)用較廣的渠系輸水建筑物之一。引洮工程位于甘肅省寒冷地區(qū)，是甘肅省規(guī)劃建設(shè)的大型跨越流域調(diào)水工程。但由于兩條供水管線末端均不具備建設(shè)大型調(diào)蓄設(shè)施的工程條件，只能通過延長總干渠供水時間來解決調(diào)蓄不足的問題，因此需要考慮冬季輸水，保證引水工程在低溫環(huán)境下的安全運行。所以對北方冬季寒冷地區(qū)箱形渡槽的溫度效應(yīng)研究具有非常重要的意義。 本文以引洮工程柳林溝箱形渡槽為例，采用有限元軟件ANSYS對箱形渡槽在冬季輸水工況下的溫度場、溫度應(yīng)力和表面保溫進行了研究分析。首先，以冬季1月份某天夜間的氣溫變化為邊界條件，采用有限元軟件計算在無保溫措施下渡槽的溫度場和溫度應(yīng)力。通過計算結(jié)果可知：當(dāng)箱形渡槽直接裸露在低溫中時，槽身外表面溫度比較低，而內(nèi)表面溫度相對較高，從而使槽身內(nèi)形成內(nèi)高外低的溫度分布狀態(tài)�？拷凵硗獗砻娴臏囟忍荻容^大，而靠近槽身內(nèi)表面的溫度梯度小。溫差最大時（5:00），在槽身橫截面X、Y方向產(chǎn)生的最大拉應(yīng)力均已超出了混凝土自身的抗拉強度設(shè)計值1.43MPa，容易導(dǎo)致槽身表面出現(xiàn)裂縫。其次，對比分析當(dāng)槽身外鋪設(shè)聚苯板和聚氨脂保溫材料的厚度分別2cm、5cm和8cm時其溫度場和溫度應(yīng)力。采用保溫材料保溫后，能有效的提高槽身外表面的溫度，減小了槽身內(nèi)外表面的溫度梯度，，從而有降低槽身的溫度拉應(yīng)力，且其與保溫板的厚度成反比。隨著保溫板厚度的增加，槽身溫度拉應(yīng)力減小的幅度也越小。保溫材料的保溫效果與其導(dǎo)熱系數(shù)成反比。最后，將最大溫差時，箱形渡槽在穩(wěn)定溫度場和非穩(wěn)定溫度場的溫度應(yīng)力進行對比分析。研究表明：無保溫板時渡槽在穩(wěn)定溫度場中的最大拉應(yīng)力與非穩(wěn)定溫度場中的最大拉應(yīng)力相差不大。采用聚苯板和聚氨酯保溫板后，槽身在穩(wěn)定溫度場和非穩(wěn)定溫度場中的拉應(yīng)力值變化也很小。 本文通過對比冬季輸水工況下箱形渡槽在無保溫措施和有保溫措施、穩(wěn)定溫度場和非穩(wěn)定溫度場這兩種情況下的溫度場和溫度應(yīng)力，了解了表面保溫對渡槽溫度場和溫度應(yīng)力的影響效果，得出一些對箱形渡槽的設(shè)計和施工有參考價值的結(jié)論，為渡槽在冬季輸水工況下應(yīng)采取的保溫措施提供理論依據(jù)和技術(shù)支持，為制定渠體的引水運行方案提供有力的科學(xué)依據(jù)。
[Abstract]:The water resources in China are unevenly distributed in time and space and lack of water per capita, which leads to the serious shortage of water resources in some areas of China. In order to solve the problem of uneven distribution of water resources and inadequate demand for water supply in China, a series of trans-regional, cross-basin and long-distance water resources allocation projects have been built. In these large-scale water conveyance projects, aqueduct is one of the widely used canal system water conveyance structures. Tao diversion project, located in cold area of Gansu province, is a large-scale water diversion project across river basin. However, since neither of the two water supply pipelines has the engineering conditions for the construction of large-scale regulating and storage facilities, the problem of insufficient regulation and storage can only be solved by extending the water supply time of the main canal, so it is necessary to consider the winter water conveyance. Ensure the safe operation of water diversion project in low temperature environment. So it is of great significance to study the temperature effect of box-shaped aqueduct in cold winter in northern China. Taking the Liulin ditch box aqueduct of Tao diversion Project as an example, the temperature field, temperature stress and surface insulation of the box-shaped aqueduct under winter water conveyance condition are studied and analyzed by finite element software ANSYS. Firstly, the temperature field and stress of the aqueduct are calculated by using finite element software under the boundary condition of the temperature variation on a certain day in January in winter. The results show that when the tank aqueduct is exposed directly to the low temperature, the outer surface temperature of the tank is relatively low, and the inner surface temperature is relatively high, which results in the formation of the internal high and outer low temperature distribution state in the tank body. The temperature gradient near the outer surface of the groove is larger than that near the inner surface of the groove. When the maximum temperature difference is 5: 00, the maximum tensile stress in the cross section XY of the trough has exceeded the design value of the tensile strength of the concrete itself at 1.43MPa, which can easily lead to cracks on the surface of the groove body. Secondly, the temperature field and thermal stress of polystyrene plate and polyurethane insulation material were analyzed when the thickness of polystyrene plate and polyurethane insulation material were 2cm / 5cm and 8cm, respectively. The heat preservation material can effectively increase the temperature of the outer surface of the groove body, reduce the temperature gradient of the inside and outside surface of the groove body, and thus reduce the temperature tensile stress of the groove body, which is inversely proportional to the thickness of the insulation board. With the increase of the thickness of the thermal insulation plate, the temperature tensile stress of the groove body decreases. The thermal insulation effect of the insulation material is inversely proportional to its thermal conductivity. Finally, the temperature stress of the tank aqueduct in the stable and unstable temperature fields is compared with the maximum temperature difference. The results show that the maximum tensile stress of the aqueduct in the stable temperature field is not different from the maximum tensile stress in the unstable temperature field. When polystyrene and polyurethane insulation boards were used, the tensile stress of the tank in the stable and unstable temperature fields also changed very little. In this paper, the temperature field and temperature stress of box aqueduct under winter water conveyance condition are compared under the condition of no heat preservation, stable temperature field and unsteady temperature field. The effect of surface insulation on temperature field and stress of aqueduct is understood, and some conclusions of reference value for the design and construction of box aqueduct are obtained. It provides the theoretical basis and technical support for the insulation measures of aqueduct under the winter water conveyance condition, and provides a powerful scientific basis for drawing up the water diversion operation scheme of the aqueduct.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TV672.3

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