本文選題：儲罐 + 軟土地基　； 參考：《中國石油大學(華東)》2015年碩士論文

【摘要】：目前,儲罐基礎及地基設計中,儲罐沉降計算一般是指地基主固結沉降的計算,很少定量考慮其蠕變沉降。為了研究軟土蠕變對儲罐沉降及不均勻沉降的影響,及儲罐軟土地基蠕變的控制措施,為大型儲罐軟土地基加固處理提供參考,本文以厚土層儲罐軟土地基為例,采用FLAC3D軟件,研究了儲油罐群充水階段的固結沉降及投入使用之后的蠕變沉降性狀,并模擬了多種常用方式對儲罐軟土地基的處理效果,得出結論如下:1)考慮軟土地基的蠕變,儲罐在正常使用過程中的沉降及不均勻沉降都比無蠕變時大很多,軟土的蠕變對儲罐沉降及不均勻沉降影響很大,儲罐設計中必須進行考慮。2)充水檢漏階段,若罐群各儲罐同步充水,則在充水完成后各儲罐沉降及不均勻沉降相同,并往相互靠近方向傾斜。若各儲罐先后充水,則先充水的儲罐沉降及不均勻沉降都較大,并按充水順序逐漸降低,但相互差距不大;最終各儲罐也基本上都往相互靠近方向傾斜。3)正常使用階段,因軟土地基的蠕變,儲罐沉降在早期階段內增長速率相對較快,隨后增速降低并保持不變;在早期短時間內,儲罐不均勻沉降呈緩慢降低趨勢,隨后逐漸增大。各儲罐充水順序及罐群效應對正常使用階段儲罐蠕變沉降影響不大。4)充水預壓法處理儲罐軟土地基,可有效降低儲罐正常使用過程中的沉降和不均勻沉降,但降低幅度不是很大。延長預壓時間能提高儲罐沉降和不均勻沉降的降低幅度,但效果不明顯。5)強夯置換法處理儲罐軟土地基,能降低儲罐沉降和不均勻沉降,但其對控制下臥軟土層的蠕變沉降效果不大;加大置換厚度及提高加固層彈性模量對儲罐沉降及不均勻沉降的降低程度很小。6)與天然軟土地基、預壓法及強夯置換法處理地基相比,CFG樁復合地基能有效地控制儲罐地基的蠕變沉降,大幅度地降低儲罐的沉降,對于大厚度儲罐軟土地基,其處理方式應首選CFG樁復合地基。增大樁長、樁徑及減小樁間距都能降低儲罐沉降,但降低幅度不大。在實際工程中,應綜合考慮經濟成本、施工難度及工期等多種綜合因素確定合理樁參數。
[Abstract]:At present, in the design of tank foundation and foundation, the calculation of tank settlement usually refers to the calculation of the main consolidation settlement of the foundation, and the creep settlement is seldom considered quantitatively. In order to study the influence of soft soil creep on tank settlement and uneven settlement, and the control measures of tank soft soil foundation creep, this paper takes the thick soil tank soft soil foundation as an example, adopts FLAC3D software, and provides a reference for the reinforcement treatment of large storage tank soft soil foundation. In this paper, the consolidation settlement and creep settlement behavior of oil storage tanks during water filling stage are studied, and the effects of various common methods on the treatment of tank soft soil foundation are simulated. The conclusion is as follows: 1) the creep of soft soil foundation is considered. The settlement and uneven settlement of storage tank in normal use are much larger than those without creep. The creep of soft soil has a great influence on tank settlement and uneven settlement. If the tanks are filled with water at the same time, the settlement and uneven settlement of the tanks are the same and inclined to each other in the direction of approaching each other. If each tank was filled with water successively, the settlement and uneven settlement of the tank filled with water were larger, and gradually decreased in the order of filling, but the difference between each other was small. Finally, the tanks were basically inclined to each other in the direction of close to each other. 3) normal service stage. Because of the creep of soft soil foundation, the tank settlement increases relatively quickly in the early stage, then decreases and remains unchanged, and in the early short time, the uneven settlement of the storage tank decreases slowly, and then increases gradually. The order of tank filling and tank group effect have little effect on the creep settlement of storage tank in normal service stage. 4) the soft soil foundation of storage tank can be treated by water filling preloading method, which can effectively reduce the settlement and uneven settlement during the normal operation of storage tank. But the reduction is not much. Prolonging preloading time can increase the decrease range of tank settlement and uneven settlement, but the effect is not obvious. 5) the dynamic tamping replacement method can treat the soft soil foundation of the storage tank and reduce the tank settlement and uneven settlement. However, it has little effect on controlling creep settlement of lying soft soil, increasing replacement thickness and increasing elastic modulus of strengthened layer can reduce tank settlement and uneven settlement very little. 6) and natural soft soil foundation, Compared with CFG pile composite foundation, preloading method and dynamic tamping replacement method can effectively control the creep settlement of storage tank foundation and reduce the settlement of storage tank by a large margin. For the soft soil foundation of storage tank with large thickness, the CFG pile composite foundation should be chosen as the first treatment method. Increasing pile length, pile diameter and decreasing pile spacing can reduce tank settlement, but the reduction range is not significant. In the actual project, the reasonable pile parameters should be determined by taking into account the economic cost, construction difficulty and time limit.
【學位授予單位】：中國石油大學(華東)
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU433

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