土木建筑与环境工程
土木建築與環境工程
토목건축여배경공정
Journal of Chongqing Jianzhu University
2015年
5期
95-100
,共6页
时变分布%扩散%硫酸盐%混凝土灌注桩
時變分佈%擴散%硫痠鹽%混凝土灌註樁
시변분포%확산%류산염%혼응토관주장
time-varying distribution%diffusion%sulfate%bored pile
硫酸盐环境下，为模拟混凝土灌注桩施工时混入的硫酸盐在桩中的时变分布行为，基于Fick 第二定律并结合初始条件与边界条件，应用分离变量法，建立硫酸盐在桩中的时变分布模型。通过算例将本文解与传统解进行比较，并进一步探讨了硫酸盐扩散分布的影响因素和影响规律。结果表明，传统解用于分析混凝土灌注桩桩中硫酸盐扩散有局限性，而本文解相对于传统解具有一定的优势。混凝土灌注桩半径越小，应用传统解分析灌注桩中硫酸盐时变分布误差较大，同时，误差随时间增大。硫酸盐在混凝土灌注桩中的时变分布呈沙漏形，沿半径方向 x ＝0处和桩表面处扩散行为明显，在 x ＝0处附近区域，初始第一年扩散速率较快，在后续的50 a 内扩散速率显著减小，但每10 a 的平均速率基本相同。扩散系数和初始浓度梯度对硫酸盐在混凝土灌注桩中的时变分布影响较大。
硫痠鹽環境下，為模擬混凝土灌註樁施工時混入的硫痠鹽在樁中的時變分佈行為，基于Fick 第二定律併結閤初始條件與邊界條件，應用分離變量法，建立硫痠鹽在樁中的時變分佈模型。通過算例將本文解與傳統解進行比較，併進一步探討瞭硫痠鹽擴散分佈的影響因素和影響規律。結果錶明，傳統解用于分析混凝土灌註樁樁中硫痠鹽擴散有跼限性，而本文解相對于傳統解具有一定的優勢。混凝土灌註樁半徑越小，應用傳統解分析灌註樁中硫痠鹽時變分佈誤差較大，同時，誤差隨時間增大。硫痠鹽在混凝土灌註樁中的時變分佈呈沙漏形，沿半徑方嚮 x ＝0處和樁錶麵處擴散行為明顯，在 x ＝0處附近區域，初始第一年擴散速率較快，在後續的50 a 內擴散速率顯著減小，但每10 a 的平均速率基本相同。擴散繫數和初始濃度梯度對硫痠鹽在混凝土灌註樁中的時變分佈影響較大。
류산염배경하，위모의혼응토관주장시공시혼입적류산염재장중적시변분포행위，기우Fick 제이정률병결합초시조건여변계조건，응용분리변량법，건립류산염재장중적시변분포모형。통과산례장본문해여전통해진행비교，병진일보탐토료류산염확산분포적영향인소화영향규률。결과표명，전통해용우분석혼응토관주장장중류산염확산유국한성，이본문해상대우전통해구유일정적우세。혼응토관주장반경월소，응용전통해분석관주장중류산염시변분포오차교대，동시，오차수시간증대。류산염재혼응토관주장중적시변분포정사루형，연반경방향 x ＝0처화장표면처확산행위명현，재 x ＝0처부근구역，초시제일년확산속솔교쾌，재후속적50 a 내확산속솔현저감소，단매10 a 적평균속솔기본상동。확산계수화초시농도제도대류산염재혼응토관주장중적시변분포영향교대。
The time-varying distribution behavior of sulfate with diffusion is investigated for bored pile internal mixed corrosion at different amounts of service times.The formulation of diffusion,based on Fick-second law combined with the initial condition and the boundary condition,for sulfate in the bored pile is formed with the method of separation of variables.A model of concrete pile is offered as an example for illustrating the time-varying distribution behavior of sulfate and making comparison with the traditional model.Further,the influence factors and their effects on the sulfate diffusion distribution are also analyzed.The results show that the application of traditional method in analysis of sulfate diffusion in bored pile has some limitations and advantages of the proposed method are obvious.The radius of bored pile decreasing induces the discrepancy of sulfate distribution increasing with employing the traditional method,while the discrepancy increases over time.The time-varying distribution of sulfate in bored pile resembles hourglass figure that along the radius direction,diffusion behavior at x=0 and surface of pile is significant.In the region near x=0,the diffusion rate of sulfate is fast during the first year and then the diffusion rate is dramatically reduced to constant rate during the 50 years.Diffusion coefficient and the concentration gradient of sulfate in bored pile have a pronounced effect on the time-varying distribution of sulfate.
