粤西滨海核电厂址强风化花岗岩物理力学特性试验研究

以广东阳江和台山两个典型花岗岩核电厂址为例，定性描述了广东粤西沿海花岗岩的分布及其风化特征，通过进行波速测试、浅层平板载荷试验、原位剪切试验等原位测试，以及常规压缩试验、固结试验等室内试验，系统分析了强风化花岗岩的主要物理与力学性质指标。结果表明：（1）花岗岩受强烈的物理风化和化学风化作用，基岩中的不稳定元素被淋溶、流失，形成了富铝型和富铁型的厚层风化壳，岩层不均匀性特点突出；（2）强风化花岗岩岩体天然含水率和孔隙比变化大，天然重度变化小，压缩性中等；（3）粒度成分对岩石物理性质的影响最大。粒度越大，物性指标越弱。粒度越小，表明岩样越致密，其物性指标越强；（4）波速的大小与岩体风化程度、粒度成分等密切相关；（5）水对强风化花岗岩抗剪强度参数中的凝聚力影响效应比内摩擦角要大，对凝聚力的弱化作用更加明显。其研究结果可为核电工程建设和优化设计提供基础参数。

Investigation of physico-mechanical properties for highly weathered granite of nuclear power station in coastal site of western Guangdong province

The distribution and weathering characteristics of granite in the western coastal site of Guangdong province are described.A series of in-situ tests are conducted,including the velocity tests,load tests and in-situ shear tests,along with laboratory tests involving conventional compression test and consolidation test.Based on test results,the physico-mechanical properties of highly weathered granite are analyzed.It is indicated that:(1) Due to strong physicochemical weathering processes,the unstable elements in bedrock are leached which further result in formation of aluminum-rich-and iron-rich types of thick weathering crust.Heterogeneity of rock is obvious.(2) Natural moisture content and void ratio of highly weathered rockmass vary greatly,while natural density and modulus of compression change moderately.(3) Particle sizes have a great impact on the physical characteristics of weathering granite.The physical indexes are stronger as the decrease of particle sizes.(4) Wave velocity is closely related to the weathering degree and particle composition.(5) Water content has more apparent effect on cohesion than friction angle.The attenuated effect on cohesion of highly weathered granite is obvious in particular.The research results can provide basic data for construction of nuclear power station and optimal design.