Bài giảng Bản đồ và bản đồ địa chất - Chương 2: Biến dạng của đá

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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 DUNG
Đá 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's
outer solid layer, the lithosphere, is made of rock.
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Biến dạng?
Deformation describes the transformations from some
initial to some final geometry
Deformation of a rock body occurs in response to a force
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?
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Lực và Ứng suất?
Force is Strength or energy as an attribute of physical
action (change the body) or movement (F = m*a)
Stress is a force applied over an area
Uniform stress = Pressure is a stress wherein the forces
act equally from all directions (X Y Z) (in fluid)
Confining stress = weight of overlying rocks is a uniform
stress (Z)
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PHÂN LOẠI?
If stress is not equal from all directions then we say that
the stress is a differential stress. Three kinds of
differential stress occur:
· Tensional stress (or extensional stress), which
stretches 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 on
their relative behavior under stress
Brittle materials have a small or large region of
elastic behavior but only a small region of ductile
behavior before they fracture.
Ductile materials have a small region of elastic
behavior and a large region of ductile behavior before
they fracture.
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Clockwise Rotation about the z-axis
.
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 HƯỞNG
Temperature - At high temperature molecules and their
bonds can stretch and move, thus materials will behave
in more ductile manner. At low Temperature, materials
are brittle.
Confining Pressure - At high confining pressure
materials are less likely to fracture because the pressure
of the surroundings tends to hinder the formation of
fractures. At low confining stress, material will be brittle
and 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