筑坝料变形模量尺寸效应及其外推模型研究  

Study on scale effect and extrapolation model of rockfill modulus

作　　者：麻志刚 吴帅峰 魏迎奇[1] MA Zhigang;WU Shuaifeng;WEI Yingqi(State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,Institute of Water Resources and Hydropower Research,Beijing 100048,China)

机构地区：[1]中国水利水电科学研究院流域水循环模拟与调控国家重点实验室,北京100048

出　　处：《水利水电技术（中英文）》2023年第4期171-186,共16页Water Resources and Hydropower Engineering

基　　金：中国电建集团重点科技项目(DJ-ZDXM-2019-3);国家自然科学基金项目(U19A2049)。

摘　　要：【目的】随着筑坝工程向高坝、大库的发展,筑坝料也向大粒径发展,但配合开展的室内试验因条件规模的限制需以缩尺的形式开展,因而引发了尺寸效应问题。针对堆石坝筑坝料变形模量尺寸效应问题,建立一个根据缩尺筑坝料室内试验值推求原型筑坝料工程实际值的变形模量外推模型。【方法】通过不同径径比下的一系列压缩试验,研究变形模量随尺度参数的变化规律;通过堆石料和砂砾石料颗粒分析试验,研究变形模量随颗粒破碎率的变化规律;根据试验规律推导给出筑坝料变形模量尺寸效应外推模型,并采用该模型对河口村面板坝坝体沉降进行预测。【结果】研究结果表明:堆石料变形模量随径径比增加而增加,砂砾石料变形模量随径径比增加而减小;变形模量随颗粒破碎率增加而减小,颗粒破碎率随径径比增加而减小;新模型使面板坝沉降预测精度提高约6.2%。【结论】根据研究结果可以推知:颗粒破碎是引起两种筑坝石料变形模量尺寸效应变化趋势相反的原因,推导给出的变形模量外推模型可以精准描述两种筑坝石料变形模量的尺寸效应规律,并提高堆石坝沉降预测精度,具有一定的适用性和合理性。为堆石坝筑坝材料尺寸效应研究提供了一个新的思路,提出的模型可以作为堆石坝变形预测的计算工具。[Objective]As the rockfill dam is built higher and higher,the rockfill size becomes bigger and bigger.Since the test equipment can not tolerate the large rockfill grains,the scaling-down rockfill is used to conduct the test.As a result,the scale effect occurs.Focusing on scale effect of the rockfill material modulus,an extrapolation-based scale effect model of rockfill modulus is proposed.[Methods]By conducting a series of tests on the samples with different ratio(R d)of the sample size to the maximum particle diameter,the variation law of the rockfill modulus according to the R d is investigated.By conducting the sieving tests on rockfill samples,the relationship between the modulus and the particle breakage factor is investigated.Based on the experimental findings,the modulus extrapolation model is proposed adopting the elastic mechanics approach.[Results]The results show that the compressive modulus of angular rockfill increases with the increasing R d,while the modulus of rounded rockfill decrease with the increasing R d;the modulus decrease with the increasing particle breakage factor and the particle breakage factor decreases with the increasing R d;the extrapolation-based modulus model improves the settlement prediction accuracy 6.2%or so.[Conclusion]The particle breakage is responsible for the opposite trend of two types of rockfill;the extrapolation-based modulus model could satisfactorily predict the modulus scale effect and improve the settlement prediction,the model is evaluated to be acceptable.A new approach for rockfill modulus scale effect is provided and the proposed model could be adopted by structural engineers to improve displacement predictions of rockfill dams.

关 键 词：尺寸效应 筑坝料 破碎率 干密度 变形模量 堆石坝 变形 影响因素 

分 类 号：TV213.4[水利工程—水文学及水资源]