杨春景　张迪　孙海枫

摘 要：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。

关键词：红层软岩;旁压试验;平板载荷试验;工程特性;空间分布特征

中图分类号：TV223.1   文献标志码：A

doi：10.3969/j.issn.1000-1379.2020.03.024

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

YANG Chunjing1，2， ZHANG Di1， SUN Haifeng3

（1.Yellow River Conservancy Technical Institute， Kaifeng 475004， China;

2.Kaifeng Yellow River Civil Engineering Experimental Center， Kaifeng 475004， China;

3.Sichuan Vocational and Technical College of Communications， Chengdu 611130， China）

Abstract：  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 increase 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 coefficient. 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.

Key words： red-bed soft rock; pressuremeter test; flat loading test; engineering characteristic;spatial distribution characteristics

第三系紅层沉积岩在我国西南、西北地区分布相当广泛，是在黄河上游地区基础工程建设中经常遇到的主要特殊岩土体类型之一[1-2]。该类型的岩石是在干旱、半干旱和高温环境条件中形成的岩土体，其颜色主要呈红褐色，岩性偏软，力学性质较差，强度和刚度较低，沉积岩的类型主要包括泥岩、泥质砂岩、砂岩、砂质泥岩和砂砾岩等， 产状主要为互层状， 统称为红层软岩[3]。受风化程度、气候条件、地形、新构造运动与水文地质条件等因素影响，不同地区的岩土体性质也存在明显差异性[4]。红层软岩是一类具有特殊物理力学性质的软弱岩体， 在开挖、卸载和暴露后容易受到降雨等气候影响， 使岩土体的强度参数和工程地质特性产生较大变异[5]。……