本文選題：軟土地基 + 反復(fù)荷載�。� 參考：《河南工業(yè)大學(xué)》2017年碩士論文

【摘要】：能夠科學(xué)合理預(yù)測(cè)軟土地基上建筑物的長(zhǎng)期沉降是保證建筑物安全使用的關(guān)鍵環(huán)節(jié)。我國(guó)軟土地基分布廣泛,隨著發(fā)展需要,不可避免在軟土地基上修建許多儲(chǔ)存糧食和石油等物質(zhì)的倉(cāng)儲(chǔ)設(shè)施。這些建筑物的特點(diǎn)是在施工結(jié)束后,于倉(cāng)儲(chǔ)設(shè)施自重產(chǎn)生的永久荷載基礎(chǔ)上多次加載和卸載,這一問(wèn)題已引起學(xué)者的廣泛關(guān)注。目前對(duì)交通荷載產(chǎn)生的反復(fù)荷載研究比較多,且方法比較成熟,但是它的變化頻率很高。而倉(cāng)儲(chǔ)設(shè)施產(chǎn)生的反復(fù)荷載屬于低頻荷載,且相對(duì)波動(dòng)較大,針對(duì)這類反復(fù)荷載作用下長(zhǎng)期沉降預(yù)測(cè)還沒(méi)有形成較成熟的計(jì)算方法。結(jié)合軟土地基復(fù)雜的工程特性,現(xiàn)有的沉降方法假設(shè)條件與實(shí)際工程中的土體不完全相符,往往造成沉降結(jié)果和實(shí)測(cè)結(jié)果相差較大。因此,一般采用基于實(shí)測(cè)數(shù)據(jù)的經(jīng)驗(yàn)公式法來(lái)進(jìn)行地基沉降預(yù)測(cè),但是是否適用這種低頻率反復(fù)荷載產(chǎn)生的沉降變形還有待研究。本文首先針對(duì)倉(cāng)儲(chǔ)設(shè)施產(chǎn)生的反復(fù)荷載特點(diǎn)進(jìn)行分析,然后對(duì)國(guó)內(nèi)外預(yù)測(cè)沉降的計(jì)算方法進(jìn)行綜述介紹,很多方法都是在太沙基一維固結(jié)理論的基礎(chǔ)之上提出的。考慮到反復(fù)荷載的無(wú)規(guī)律性,采用使用廣泛的基于實(shí)測(cè)數(shù)據(jù)的擬合經(jīng)驗(yàn)公式法,并對(duì)其中常用的幾種擬合曲線法進(jìn)行單獨(dú)分析,列出其中的優(yōu)點(diǎn)和局限性,結(jié)合倉(cāng)儲(chǔ)設(shè)施的結(jié)構(gòu)特點(diǎn),利用Origin軟件的數(shù)據(jù)處理功能提出雙曲線法和指數(shù)曲線法、三點(diǎn)法可以用于倉(cāng)儲(chǔ)設(shè)施的沉降預(yù)測(cè)。利用工程實(shí)例驗(yàn)證這三種方法的可行性,通過(guò)這三種方法擬合值與實(shí)測(cè)值的對(duì)比分析,得出指數(shù)曲線法擬合度很高更適合倉(cāng)儲(chǔ)設(shè)施的長(zhǎng)期沉降,但是這種方法只針對(duì)運(yùn)營(yíng)期的沉降預(yù)測(cè)。因此,本文還提出了另外一種方法—疊加法,利用施工期的沉降觀測(cè)數(shù)據(jù)進(jìn)行地基沉降預(yù)測(cè)。疊加法的原理就是根據(jù)倉(cāng)儲(chǔ)設(shè)施在使用期間重復(fù)著加載-卸載-加載產(chǎn)生多級(jí)荷載的過(guò)程,對(duì)無(wú)規(guī)律的反復(fù)荷載進(jìn)行分析,把荷載進(jìn)行分級(jí)處理,大小相近的為一個(gè)級(jí)別,得到每個(gè)級(jí)別荷載作用下的以指數(shù)形式發(fā)展的沉降擬合曲線,所有沉降曲線加在一起為總沉降,最后用實(shí)例驗(yàn)證疊加法的科學(xué)合理性。通過(guò)對(duì)軟土性質(zhì)和倉(cāng)儲(chǔ)設(shè)施產(chǎn)生的反復(fù)荷載分析,提出了指數(shù)曲線法和疊加法適合預(yù)測(cè)軟土地基長(zhǎng)期沉降,疊加法還可以預(yù)測(cè)多級(jí)荷載下的地基沉降,并驗(yàn)證了它們的合理性,以便以后能夠有效合理的為沉降預(yù)測(cè)提供依據(jù)。
[Abstract]:It is the key to ensure the safe use of buildings to predict the long-term settlement of buildings on soft soil foundation scientifically and reasonably. The soft soil foundation is widely distributed in China. With the need of development, it is inevitable to build a lot of storage facilities to store food and oil on the soft soil foundation. The characteristics of these buildings are that they are loaded and unloaded many times on the basis of the permanent load caused by the self-weight of storage facilities after the construction. This problem has attracted extensive attention of scholars. At present, there are many researches on the repeated loads caused by traffic loads, and the methods are more mature, but their frequency of change is very high. However, the cyclic load generated by storage facilities belongs to low-frequency load and is relatively fluctuating. There is no mature calculation method for long-term settlement prediction under this kind of repeated load. Combined with the complex engineering characteristics of soft soil foundation, the existing settlement method assumption condition is not completely consistent with the actual soil mass, which often results in a big difference between the settlement results and the measured results. Therefore, the empirical formula method based on the measured data is generally used to predict the settlement of the foundation, but whether it is applicable to the settlement deformation caused by the low frequency repeated load has yet to be studied. In this paper, the characteristics of repeated loads generated by storage facilities are analyzed firstly, and then the calculation methods of predicting settlement at home and abroad are summarized and introduced. Many of the methods are based on the one-dimensional consolidation theory of Terzaghi. Considering the irregularity of repeated load, the empirical formula method based on measured data is widely used, and several fitting curve methods commonly used are analyzed separately, and the advantages and limitations of these methods are listed. Combined with the structural characteristics of storage facilities, the hyperbolic method and exponential curve method are proposed by using the data processing function of Origin software. The three-point method can be used to predict the settlement of storage facilities. The feasibility of these three methods is verified by an engineering example. Through the comparison and analysis of the fitting values and the measured values of the three methods, it is concluded that the high fitting degree of exponential curve method is more suitable for the long-term settlement of storage facilities. But this method is only used to predict the settlement of the operation period. Therefore, another method, the superposition method, is put forward in this paper to predict the foundation settlement by using the settlement observation data during the construction period. The principle of superposition method is that according to the process of repeated loading, unloading and loading of storage facilities during use, the random repeated loads are analyzed, and the loads are classified and treated, and the same size is a grade. The fitting curve of the settlement developed in exponential form under each grade load is obtained. All the settlement curves are added together as the total settlement. Finally, the scientific rationality of the superposition method is verified by an example. Through the repeated load analysis of soft soil properties and storage facilities, the exponential curve method and superposition method are proposed to predict the long-term settlement of soft soil foundation, and the superposition method can also predict the foundation settlement under multistage load, and verify their rationality. In order to effectively and reasonably provide the basis for settlement prediction in the future.
【學(xué)位授予單位】：河南工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TU433;TU447

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本文編號(hào)：1819929