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GEOPET

BÀI GIẢNG CHỈ DÀNH CHO SINH VIÊN THEO HỌC LỚP ĐỊA CHẤT KIẾN TRÚC & ĐO VẼ BẢN ĐỒ ĐỊA CHẤT

TS. Nguyễn Huỳnh Thông

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NỘI DUNGĐá là gì? Phân loại Đá?

Biến dạng là gì? (Definition)

Lực và ứng suất? (Stress & Strain)

Các giai đoạn biến dạng? (Stage)

Các yếu tố ảnh hưởng biến dạng? (Factor)

Đặc tính biến dạng dẻo-đàn hồi của Thạch quyển?

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Đá là gì? Phân loại Đá?Rock is a combination one or more minerals. The Earth'souter solid layer, the lithosphere, is made of rock.

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Biến dạng?Deformation describes the transformations from someinitial to some final geometryDeformation of a rock body occurs in response to a force

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Lực và Ứng suất?Force is Strength or energy as an attribute of physicalaction (change the body) or movement (F = m*a)Stress is a force applied over an areaUniform stress = Pressure is a stress wherein the forcesact equally from all directions (X Y Z) (in fluid)Confining stress = weight of overlying rocks is a uniformstress (Z)

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PHÂN LOẠI?If stress is not equal from all directions then we say thatthe stress is a differential stress. Three kinds ofdifferential stress occur:· Tensional stress (or extensional stress), whichstretches rock;· Compressional stress, which squeezes rock; and· Shear stress, which result in slippage and translation.

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CÁC GIAI ĐOẠN BIẾN DẠNG(Stages of Deformation)

Elastic Deformation -- wherein the strain is reversible.Ductile Deformation -- wherein the strain is irreversible.Fracture - irreversible strain wherein the material breaks.

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We can divide materials into two classes that depend ontheir relative behavior under stress

Brittle materials have a small or large region ofelastic behavior but only a small region of ductilebehavior before they fracture.

Ductile materials have a small region of elasticbehavior and a large region of ductile behavior beforethey fracture.

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Clockwise Rotation about the z-axis

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Translation Parallel to the Y axis

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Strain or Distortion

Dilation

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Homogeneous Strain

Homogeneous Deformation - Pure Shear

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Homogeneous Deformation - Simple Shear

Heterogeneous or Inhomogeneous strain

Leads to distorted complex forms

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CÁC YẾU TỐ ẢNH HƯỞNGTemperature - At high temperature molecules and theirbonds can stretch and move, thus materials will behavein more ductile manner. At low Temperature, materialsare brittle.

Confining Pressure - At high confining pressurematerials are less likely to fracture because the pressureof the surroundings tends to hinder the formation offractures. At low confining stress, material will be brittleand tend to fracture sooner.

Strain rate ?

Composition ? 17

BIẾN DẠNG GIÒN-DẺO CỦA THẠCH QUYỂN

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THANK YOU !

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CHUẨN BỊ:• CHƯƠNG 3: KIẾN TRÚC PHÂN LỚP