sir clearly tell me the method how to differntiate between fractures and joints
A fracture is any local separation or discontinuity plane in a geologic formation, such as a joint or a fault that divides the rock into two or more pieces. A fracture will sometimes form a deep fissure or crevice in the rock. Fractures are commonly caused by stress exceeding the rock strength, causing the rock to lose cohesion along its weakest plane. Fractures can provide permeability for fluid movement, such as water or hydrocarbons. Highly fractured rocks can make good aquifers or hydrocarbon reservoirs, since they may possess both significant permeability and fracture porosity.Fractures in rocks can be formed either due to compression or tension. Fractures due to compression include thrust faults. Fractures may also be a result from shear or tensile stress. Some of the primary mechanisms are discussed below.(wikipedaia_)
n geology the term joint refers to a fracture in rock where the displacement associated with the opening of the fracture is greater than the displacement due to lateral movement in the plane of the fracture (up, down or sideways) of one side relative to the other. Typically, there is little to no lateral movement across joints. This makes joints different from a fault which is defined as a fracture in rock in which one side slides laterally past the other with a displacement that is greater than the separation between the blocks on either side of the fracture. Joints normally have a regular spacing related to either the mechanical properties of the individual rock or the thickness of the layer involved. Joints generally occur as sets, with each set consisting of joints sub-parallel to each other.
Joints form in solid, hard rock that is stretched such that its brittle strength is exceeded (the point at which it breaks). When this happens the rock fractures in a plane parallel to the maximum principal stress and perpendicular to the minimum principal stress (the direction in which the rock is being stretched). This leads to the development of a single sub-parallel joint set. Continued deformation may lead to development of one or more additional joint sets. The presence of the first set strongly affects the stress orientation in the rock layer, often causing subsequent sets to form at a high angle to the first set.
Joint sets are commonly observed to have relatively constant spacing, which is roughly proportional to the thickness of the layer(wikipedia)
Joint and fractures in rocks due to the differential movements of rock mass-You can read the wikipedia source clearly indicated formation differences of joint and fractures
You can also see major joints-vertical joints-columnar joints -etc
You can aslso refer journals geotechnical engineering -rock mass classification-engineering classification of rocks-U can aslso refer Structural geology by B.P Billings standard book given all details
You can also refer field geolpogy books clearly illustrate further information
Generally joints-fractures-faults and unconformites are listed under structural discontinuities
Yu can read my book-ENGINEERING GEOLOGY-By D.VENKAT REDDY-Vikaspublications-India given -separate chapter on structural geology its importance in civil engineering application
Read book review
Engineering Geology by D.Venkat Reddy, Vikas Publishing House Pvt. Ltd., New Delhi, (2010), 658 pages.
Recently a new book released entitled "Engineering Geology" written by Dr. D. Venkat Reddy, Professor of Engineering Geology, National Institute of Technology, Surathkal, Karnataka published by Vikas publishing house Pvt. limited, New Delhi. This book provides an excellent understanding of applied facet of geological science and engineering.
The first few chapters of book explained very noticeably and concisely basic understanding of diverse geological aspects which is required for any field geologist, engineer and practicing scientist.
The initial chapter present a concise and articulate introduction to various branches and sub branches of geological sciences and engineering. Subsequently the book deals with the earth interior and importance of understanding the earth crust, along introduction to the engineering geological phenomenon and its applications for development of society. The fundamentals of mineralogy, petrology and structural geology have been given passable concentration. The geomorphological frame work of hydrosphere comprising the structural drainage, marine erosion and ground water have been discussed from the point of view of civil engineers and engineering geologist. A good discussion has been specified of seismic hazards and structural protective design to be considered in earthquake prone areas.
The author has discussed specific problem encountered in civil and mining engineering such as building sites, slope stability of natural rockmass as well as dump material, geo-hazards, pillar design, rock mechanics, bridge design, dam and reservoirs, tunnel and large size tunnel excavation. Application and utility of remote sensing and GIS have been briefly explained. Chapter of Stratigraphy of India and environmental geology is very useful for earth scientist and engineers for day to day working on the project site.
The book provide an excellent understanding of engineering geology and has enormous use to earth scientist, practising engineer and civil engineers who can exchange ideas during execution of projects. This book provides support and practical guidance to those seeking help to guard the Mother earth while understanding it appropriately and accurately. In addition, the book is suitable for student of geology, geophysics, civil and mining engineers. The book provides an excellent understanding of rock engineering which will immensely benefit student, teachers, professionals and designer.
Professor D.Venkat Reddy deserve our gratitude for providing priceless reading material for practising geoscientist who are fascinated for meaning full balance to eco- system for sustainable development. It is equally good for a graduate who has just going ahead his career, to senior professional concerned in capitalising on his vast experience, this book provides solid possibility.
Department of Earth Sciences,
Indian Institute of technology,Bombay,
Prof D.Venkat Reddy
Editor in chief IJEE journasl