白鹤滩水电站高填方工程砾石填料的物理力学特性

Physical and Mechanical Properties of Gravelly Soils Used in High Fill Project of Baihetan Hydropower Station

摘要:

白鹤滩水电站是全球单机容量最大、在建规模最大的水电站。为避免水库蓄水后巧家县城区中的移民安置区被淹，需进行高填方工程，填筑材料以当地砾石土料为主。依托白鹤滩水电站高填方工程，对砾石填料进行颗粒分析、击实试验、压缩试验和三轴剪切试验等室内土工试验以及现场碾压试验。研究表明：填料的压实特性与砾石质量分数有关，粒径大于5mm的砾石质量分数在40%~70%时，填料较易形成密实骨架结构，表现出较好的可压实性和力学性能。在现场碾压过程中，需从填料的砾石质量分数及现有设备等因素来综合控制压实含水率。压实度为0.95和0.97的砾石填料的压缩特性及抗剪强度有明显差异。同时，根据填料试样的应力、应变关系确定了邓肯-张双曲线模型的参数。试验结果为白鹤滩移民区高填方工程的填料配比设计、力学与施工参数的选取提供参考。

Abstract:

Baihetan Hydropower Station is the largest hydropower station under construction and has the world’s largest single-unit capacity. In order to avoid the flooding of the resettlement area of Qiaojia County when the reservoir is impounded， a high filling project is required. The filling material is the locally obtained gravelly soil. In this study， the particle size analysis test， the compaction test， the compression test， and the triaxial test as well as the onsite rolling test are conducted on the gravelly soils. The results show that the compaction characteristics of the soils depend on the gravel content. When the gravel （i.e.， particle size larger than 5 mm） content is 40%~70%， the soils will form a dense skeleton structure and show better compactability and mechanical properties. During the onsite rolling compaction process， it is necessary to control the moisture content based on the gravel content of the soils and the rolling equipment adopted. Gravelly soils with compaction degrees of 0.95 and 0.97 show significant differences in their compression properties and shear strength. Meanwhile， according to the stress-strain relationships of the soils， the parameters of the Duncan-Chang hyperbolic model are determined. The test results provide an important reference for the gradation and compaction design of the filler as well as the parameters of the filler for the Baihetan high fill project.