柴家峡红层软岩原位工程特性的空间分布特征

Study on Space Distribution of In-situ Engineering Parameters of Red-Bed Soft Rock in Chaijiaxia Area

为了获得黄河上游第三系红层软岩承载力和变形参数沿水平向及垂直向的变化规律,利用旁压试验和平板载荷试验对分布于柴家峡水利枢纽的红层软岩展开研究。结果表明:红层软岩的地基承载力和变形参数在较小水平距离的范围内有较大变化,不同水平位置的试验结果与岩土体的埋深、含水率及风化程度等有关;在同一水平位置处的承载力和变形模量,沿垂直向深度呈线性上升的规律,物理化学风化和地应力作用使得地表与深层岩体的承载力及变形特征有所差异。研究结果揭示了红层软岩的工程特性具有明显空间变异性的特点,导致跨度较大的构筑物布置在红层软岩地段时常会产生不均匀沉降。

In order to obtain the vertical and horizontal parameters of the bearing capacity and deformation characteristics of soft rock in the Chaijiaxia area,the soft rock of a dam foundation of diversion channel was studied based on the pressuremeter tests and plate load tests.The results show that the bearing capacity and deformation parameters of soft rock in red⁃bed vary greatly in a small horizontal distance,and in⁃crease linearly along the depth vertically.And the test results are related to the depth,moisture content and weathering degree of rock and soil.The modulus of deformation can be obtained from the modulus of pressuremeter tests at different depths by means of the structural coeffi⁃cient.Weathering and stress states make the bearing capacity and denaturation characteristics of surface and deep rock mass are various from each other.The research results reflect the spatial distribution characteristics of mechanical and deformation characteristics of soft rock in red beds,thus the uneven settlement of structures with large span often occurs in red⁃bed soft rock.The test results can provide a certain reference for the selection of design parameters of related strata and also provides a reference for the formulation of relevant formation in⁃situ test scheme.