Effects of Physical Properties Mechanical State on the Deformation of Porous Sediments

多孔沉积物的力学行为对于 对增生棱柱体变形的理解，沉降 和扩张盆地，以及其他环境中，“软” 沉积物受到构造应力或重力应力的作用。 不幸的是，物理性质之间的关系， 这些沉积物的机械状态和结构组构， 很少有人知道，这阻碍了发展， 定量地质力学模型 一系列的机械测试 已制成中等多孔（20-40%）粉质粘土（均 自然和人工巩固），这将使我们能够 将这些材料的物理性质和机械状态关联起来， 变形过程中产生的具有构造组构的沉积物。 研究了室内固结的强度曲面 沉积物，如有效平均值的三维空间所示 平均应力下的应力、差应力和孔隙比 增生棱柱体中典型的地质条件。 为 我们在现场测量的盆地序列中的天然沉积物 并分析了在铺设过程中产生的故障织物 平行缩短 用于研究自然变形的 沉积物，我们有几个样品从DSDP网站在南开 增生棱柱 结构组构分析包括光学 用于测量整体和内部几何形状的显微镜 在破坏区，孔隙度变化的微探针研究， 以及用于织物各向异性和应变的X射线极图测角法。

The mechanical behavior of porous sediments is important for the understanding of deformation in accretionary prisms, subsiding and spreading basins, and other settings in which "soft" sediments are subjected to tectonic or gravitational stresses. Unfortunately the relationships among physical properties, mechanical state, and structural fabric for these sediments are very poorly known, which has impeded the development of quantitative geomechanical models. A series of mechanical tests have been made moderately porous (20-40%) silty clays (both natural and artificially consolidated) that will allow us to correlate the physical properties and mechanical state of these sediments with the structural fabrics produced during deformation. We investigated strength surface for laboratory consolidated sediments, as depicted in a 3-dimensional space of effective mean stress, differential stress, and void ratio, at mean stresses typical of geologic conditions in accretionary prisms. For natural sediments from basinal sequences we measured in-situ strength and analyze the failure fabrics produced during bedding parallel shortening. For the study of naturally deformed sediments we have several samples from DSDP sites in the Nankai accretionary prism. Structural fabric analyses included optical microscopy for measurement of the overall and internal geometries of the failure zones, microprobe studies for porosity variations, and x-ray pole figure goniometry for fabric anisotropy and strain.