Model tests on size effects of dam rockfill materials
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摘要: 随着筑坝工程向高坝、大库的发展,筑坝料也向大粒径发展,而室内试验因条件规模的限制需以缩尺的形式开展,进而引发尺寸效应问题。对此,推导建立了变形特性的尺寸效应模型,模型考虑了颗粒破碎、侧向变形、干密度及荷载水平等因素,并选取堆石料和砂砾石料两类典型筑坝材料开展了120~1000 mm试样尺度下的系列压缩实验,揭示了径径比、破碎率与尺寸效应的相关关系。研究结果表明:颗粒破碎率随径径比增加而减小,压缩模量随颗粒破碎率增加而减小,堆石料压缩模量随径径比增加而增加,砂砾石料压缩模量随径径比增加而减小。试验结果与模型计算结果较一致,证明模型具有一定的适用性和合理性。Abstract: With the development of dam construction towards higher dams and larger storage capacity, the dam materials are also developing towards larger particle sizes. However, due to the limitations in conditions and scale, the soil tests need to be conducted in a scaled form, which has led to the issues related to size effects. In this study, a size effect model for the deformation characteristics of dam soil and stone materials is derived and established taking into account the factors such as particle breakage, lateral deformation, dry density and load level. A series of compression experiments are conducted on two typical types of dam building materials, rockfill and gravel with sample sizes ranging from 120 to 1000 mm, revealing the correlation between the size effects of diameter to diameter ratio and crushing rate. The research results indicate that the particle breakage rate decreases with the increase of the diameter to diameter ratio, the compression modulus decreases with the increase of the particle breakage rate, the deformation modulus of the rockfill materials increases with the increase of the diameter to diameter ratio, and the compression modulus of the gravel materials decreases with the increase of the diameter to diameter ratio. The experimental results are consistent with the the calculated ones by the model, proving that the proposed model is of certain applicability and rationality.
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Keywords:
- dam material /
- size effect /
- crushing rate /
- diameter ratio /
- compression modulus
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全球性的气候问题与突发自然灾害使得岩土及地下工程灾变问题不断凸现,给岩土工程安全与运营构成巨大挑战。岩土体作为地球表面最为广泛存在的地质材料具有复杂的物理力学特性与显著的时空变异性。岩土工程物理模拟试验技术通过融合多学科知识模拟和再现岩土体在自然与工程状态下的物理力学行为,为复杂岩土工程问题的解决提供强力支撑。“交通强国”等重大国家战略的实施也给岩土工程带来了巨大的历史机遇。岩土工程防灾减灾问题由于其普遍性、迫切性和前沿性也成为岩土及地下工程领域研究的新热点。随着科技的进步,岩土工程物理模拟试验技术也正从传统的重力场模拟、离心试验,向数字与智能化转变,而世界级超大型试验设备的建设,更将极大驱动我国岩土工程物理模拟试验技术的未来发展。
为促进我国岩土工程物理模拟试验技术学术交流,由中国水利学会岩土力学专业委员会和中国土木工程学会土力学及岩土工程分会共同主办,交通运输部天津水运工程科学研究院、南京水利科学研究院、中交天津港湾工程研究院有限公司以及天津大学承办的第十届岩土工程物理模拟学术研讨会于2024年8月在天津市滨海新区举行。本届会议是继武汉(2011年)、杭州(2013)、北京(2017)、喀什(2023)会议后全国岩土工程物理模拟试验技术领域的又一次学术盛会。会议筹备期间共收到投稿论文113篇,经过审稿委员会的审议向《岩土工程学报》(增刊)推荐稿件51篇,并在学报2024年增刊1专刊出版。同时,本届研讨会举办了砂土场地桩基水平承载力平行试验,并以特邀报告、主题报告、青年学者报告等在内的形式开展广泛深入的交流,展现最新模拟技术和研究成果,探讨岩土工程物理模拟试验技术在交通强国基础设施建设与防灾减灾研究中的应用,以促进岩土工程物理模拟试验技术对我国重大战略和重大工程的技术支撑作用。
感谢对本届会议召开鼎力相助的交通运输部天津水运工程科学研究院及各有关单位,感谢向本届会议投稿的各位专家和同行,感谢审稿专家对本次会议审稿工作的辛勤付出。尤其是《岩土工程学报》编辑部,为使本届会议的论文集面世,做了大量工作,专门编辑出版了本期增刊,特此表示感谢。
第十届全国岩土工程物理模拟学术研讨会组委会 -
表 1 尺寸效应试验方案
Table 1 The size effect test plan
径径比Rd 装样最大粒径/mm 试件直径D/mm 5 200 1000 12.5 80 25 40 5 100 500 12.5 40 25 20 6 20 120 12 10 24 5 表 2 尺寸效应模型参数
Table 2 Model parameters of size effects
名称 b ξ 砂砾石料 2.20 36 6 2.67 — — 堆石料 1.35 64 3 2.67 1.15 0.38 -
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