【摘要】：裂縫是混凝土結(jié)構(gòu)一個(gè)很主要的安全隱患,圍繞混凝土裂縫的開裂及裂縫的擴(kuò)展一直是國內(nèi)外學(xué)者研究的重點(diǎn)�；炷两Y(jié)構(gòu)的破壞開裂是一個(gè)涉及到力學(xué)與材料學(xué)的綜合問題。混凝土斷裂力學(xué)是專門研究混凝土材料破壞開裂的一門學(xué)科,其引入許多新的關(guān)于裂縫問題的概念和方法,它比其他常規(guī)強(qiáng)度理論更適合于混凝土材料,它專注于混凝土材料本身的初始缺陷,分析在荷載作用下這種初始缺陷的發(fā)展規(guī)律,進(jìn)而提出解決裂縫的安全設(shè)計(jì)準(zhǔn)則。針對目前混凝土斷裂問題研究存在的問題,本文通過試驗(yàn)研究與數(shù)值模擬進(jìn)行了如下工作:(1)與其他成熟的工程學(xué)科相比,混凝土斷裂力學(xué)仍然是一個(gè)發(fā)展中的領(lǐng)域,其很多研究還不成熟。本文在混凝土斷裂理論研究成果的基礎(chǔ)上,進(jìn)行了跨高比S/D)= 4的三點(diǎn)彎曲斷裂試驗(yàn),試驗(yàn)過程中采集了荷載—裂縫張開口位移曲線(P-CMOD曲線)和荷載—位移曲線(P-δ曲線),使用P-δ曲線計(jì)算了三點(diǎn)彎曲試件的斷裂能Gf,并依據(jù)試驗(yàn)數(shù)據(jù)進(jìn)行了混凝土斷裂韌度K1c的計(jì)算。(2)由于混凝土多裂縫問題的復(fù)雜性,本文進(jìn)行了多個(gè)尺寸預(yù)制多裂縫混凝土梁的三點(diǎn)彎曲和四點(diǎn)彎曲試驗(yàn),并探索了不同加載方式下試件斷裂的破壞荷載、裂縫走向等問題。試驗(yàn)過程中采集了各條裂縫的荷載—裂縫張開口位移曲線(P-CMOD曲線),通過曲線分析,我們能清晰的了解到相同時(shí)刻各條裂縫的進(jìn)展情況,同時(shí),也記錄了試件的破壞形態(tài)圖。(3)依據(jù)試驗(yàn)測定的基礎(chǔ)數(shù)據(jù),建立數(shù)值計(jì)算模型,基于虛擬裂縫模型方法對試件進(jìn)行數(shù)值模擬計(jì)算,并與試驗(yàn)結(jié)果進(jìn)行對比分析,結(jié)果表明,數(shù)值模擬與試驗(yàn)結(jié)果基本吻合,驗(yàn)證了所用模型的正確性。
[Abstract]:Cracks are a major safety hazard in concrete structures. Cracks and crack propagation around concrete have been the focus of research by scholars at home and abroad. The discipline introduces many new concepts and methods about crack problems, which are more suitable for concrete materials than other conventional strength theories. It concentrates on the initial defects of concrete materials, analyzes the development law of such initial defects under load, and then puts forward safety design criteria for cracks. The following work has been done in this paper: (1) Compared with other mature engineering disciplines, the fracture mechanics of concrete is still a developing field, and many of its research is still immature. In the three-point bending fracture test, load-crack opening displacement curve (P-CMOD curve) and load-displacement curve (P-delta curve) were collected. The fracture energy Gf of three-point bending specimens was calculated by P-delta curve, and the fracture toughness K1c of concrete was calculated according to the test data. (2) Because of the multi-crack problem of concrete. In this paper, three-point bending and four-point bending tests of precast multi-crack concrete beams with different sizes are carried out, and the failure loads and crack strikes of specimens under different loading modes are explored. It can clearly understand the progress of each crack at the same time, and also record the failure pattern of the specimen. (3) According to the basic data measured by the test, a numerical calculation model is established. Based on the virtual crack model method, the numerical simulation of the specimen is carried out and compared with the experimental results. The results show that the numerical simulation and the test are carried out. The results are basically consistent and verify the correctness of the models used.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TV331

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本文編號：2184198