水壓力環境中混凝土經歷循環荷載后的抗壓強度

王乾峰　劉云賀　彭剛　鄒三兵

摘要：

研究了水壓力環境中混凝土在經歷循環荷載后的動態壓縮強度，分析了水壓力和循環次數對混凝土強度的影響。試驗應變速率為10-5/s、10-4/s、10-3/s和10-2/s，水壓為0～10 MPa。試驗結果表明，在不同水壓力下飽和混凝土的強度都隨應變速率提高而增加，也隨水壓力提高呈增加地趨勢。在相同水壓力下，應變速率越高，混凝土強度提高越顯著。飽和混凝土經過循環荷載后，其強度隨荷載循環次數的增加呈現出先提高后降低的現象。應變速率越高，混凝土強度最大時所對應的荷載循環次數也相應增加。還構建了飽和混凝土強度與應變速率、水壓力的關系，其與試驗數據吻合較好。進一步引入了管道孔隙模型，并基于汞壓法的原理和孔隙分布特點，考慮混凝土孔隙的微觀結構解釋了孔隙水對混凝土強度的作用機理。

關鍵詞：

混凝土；水壓力；循環荷載；應變速率；動態性能；孔隙結構

中圖分類號：TU528.1

文獻標志碼：A文章編號：16744764（2017）02013208

Abstract：

The dynamic compression strength of concrete which undergone cyclic loading and subjected to water pressure was carried out， and effect of water pressure and cyclic times on strength of concrete was analyzed. Strain rates of tests were 10-5/s， 10-4/s， 10-3/s and 10-2/s， and water pressure ranged from 0 to 10 MPa. The results showed that strength of saturated concrete under different water pressure increased with the increasing strain rate， and that also increased with the increasing water pressure. Under the same water pressure， the concrete strength increased more significantly when the strain rate was higher. After cyclic loading， strength of saturated concrete showed the phenomenon of the first increase and then decreased as the number of load cycles increased. The higher the strain rate， the greater number of load cycles with maximum concrete strength. The relationships between concrete strength and strain rate， water pressure were established， which was in good agreement with the experimental data. Furthermore， the pipe pore model was introduced， and the mechanism of pore water on the concrete strength was explained and based on the principle of mercury intrusion porosimetry and pore distribution.

Keywords：

concrete； water pressure； cyclic loads； strain rate； dynamic property； pore structure

混凝土是大壩、港口和橋墩等結構中普遍使用的材料，這些結構經常處于水環境中，在結構表層部分會形成與水壓力相等的孔隙水壓力。而且，這些結構不僅承受靜態荷載的作用，還要遭受地震或是動水壓力的沖擊。因此，有必要對水環境中的混凝土材料開展動態荷載作用下的試驗研究。

許多學者考慮到結構深部承受不可忽略的水壓力，開展水環境作用或孔隙水壓力作用對混凝土強度影響的研究。李宗利等[1]考慮到高壓水滲透和孔隙水壓力對混凝土的影響，采用高水壓力飽和混凝土，結果表明混凝土的抗壓強度、劈裂抗拉強度和彈性模量都隨孔隙水壓力的增加逐漸降低。……