In this chapter we will define, describe, and determine the shear strength of soils. Once again i welcome you this lecture and i have mentioned in my last lecture that i have completed the shear strength. Civil engineering mcqs shear strength of soils notes pdf civil engineering notes % civil engineering mcqs no. Shear strength of soil, mohrcoulomb failure analysis, direct shear test, stress and strain controlled tests. Soil reinforcement an overview sciencedirect topics.
Engineering properties of soils based on laboratory testing prof. Soil failure usually occurs in the form of shearing along internal surface within the soil. Apr 18, 2018 rrb je 2019 cbt 2 exam lec 15 shear strength of soil part 1 civil engg shubham sir duration. The contact between soil particles is mainly due to friction and the corresponding stress between the soil grains is called the effective or intergranular stress s.
In the long term, we would use a drained shear strength model to determine whether or not shear failure or a slope failure would occur. Shear strength of soils notes pdf civil engineering mcqs. One important a spect to consider is the approach utilized to as sess the shear strength o f the soil being excavated. Introduction to soil mechanics geotechnical engineering. Chapter 5 engineering properties of soil and rock 5. Shear strength is a very important property of soils. For simple beams, support reactions for statically determinant beams, relationship between bending moment and shear force, shear force and bending moment diagrams. Determination of the shear strength parameters of an.
Where, cu undrained shear strength of soft layer, psf ds thickness of soft soil layer, ft gama unit weight of fill soil, psf theta angle of fill slope, degrees h height of fill, ft also used in the past hgama pdf 1. Shear strength of soil in hindi soil mechanics lecture 1. Module 4 stressstrain relationship and shear strength of soils. Embankment strip footing shear failure of soils soils generally fail in shear at failure, shear stress along the failure surface mobilized shear resistance reaches the shear strength.
Compaction increases the shear strength of soil and reduces its compressibility and permeability 19, 21. On the other hand, if the wall moves into the soil, then the soil mass is compressed. Soil mechanics, geotechnical engineering i usb media storage type. A national science foundation sponsored workshop on the shear strength of liquefied soil was held at the university of illinois at urbanachampaign on april 1819, 1997. Addis ababa university, faculty of technology, department of civil engineering soil mechanics ii. The shear resistance of soil is a result of friction and interlocking of particles, and possibly cementation or bonding at particle contacts. The concept of shear strength in unsaturated soils is discussed in chapter 6. During testing, the porewater pressure is measured. Determination of the shear strength parameters of an unsaturated soil using the direct shear test j.
The maximum shear stress theory states that failure occurs when the maximum shear stress from a combination of principal stresses equals or exceeds the value obtained for the shear stress at yielding in the uniaxial tensile test. Shear strength mobilization is c, at the periphery of the soil cylinder and decreases lineaarly to zero at the center. Shear strength is a term used in soil mechanics to describe the magnitude of the shear stress that a soil can sustain. Krishna reddy, uic 1 introduction soil is one of the most important engineering materials. Undrained shear strength of a soil su is the shear strength of a soil when sheared at constant volume. It is also required for clay soil to evaluate the long term stability.
The following set of lecture notes cover every major topic discussed in class. Attaullah shah shear failure soils generally fail in shear shear failure shear failure mechanism shear failure of soils soils. After a successful completion of the course, the students will be able. Civil engineering mcqs shear strength of soils notes pdf civil engineering notes %. Conclusion shear strength of soil is most important property. This test gives the undrained strength of the soil, and the undisturbed and remolded strengths obtained are also used for evaluating the sensitivity of the soil. Shear strength of soil, mohrcoulomb failure analysis, direct shear test, stress and strain controlled tests welcome back. Strength of different materials steel tensile strength concrete compressive strength soil shear strength presence of pore water complex behavior 3. Shear strength of soil, introduction and concepts, mohrcoulomb failure analysis. Determine the strength characteristics of the soil. The laboratory vane shear test is used for the measurement of undrained shear strength of cohesive soils of low shear strength less than about 0. Since the soil becomes dense, its permeability gets decreased.
Murthy 10 explained that when an earth dam is properly compacted, the shear strength of the material is increased and dam becomes more stable. Nicholson, in soil improvement and ground modification methods, 2015. Nov 26, 2014 conclusion shear strength of soil is most important property. Ghosh department of civil engineering indian institute of technology kanpur lecture 39 shear strength of soil b keywords. The concept is used by geotechnical engineers in estimating the bearing capacity of foundations and in assessing the stability of retaining walls, slopes, and embankments and the design and construction of highway and airfield pavements. Thus, structural strength is primarily a function of shear strength. Drained shear strength is computed for solving all field problems in sandy soils.
Scribd is the worlds largest social reading and publishing site. Where, cu undrained shear strength of soft layer, psf ds thickness of soft soil layer, ft gama unit weight of fill soil, psf theta angle of fill slope, degrees h height of fill, ft also used in the past hgama shear strength and thickness the thickness of the pile cap is initially determined based on the following key parameters. A sample of this material is tested in a triaxial compression test consolidated, undrained. Determine the amount of consolidation occuring the soil. Indian institute of technology, kanpur 1 module 4 lecture 21 pore water pressure and shear strength 5 topics 1. Now, in this section of the article, you will be able to get access to the advanced soil mechanics 4th edition pdf free download file in. Understand the difference between drained and undrained shear. Nptel civil engineering unsaturated soil mechanics.
Shear strength of soil necessity of studying shear strength of soils. Welcome back to the course geology and soil mechanics. Numerical problems on shear strength calculation, shear strength parameters, triaxial test. A free powerpoint ppt presentation displayed as a flash slide show on id. Design manual engineering properties of soil and rock. Every aspect of soil mechanics starting from origin of soil to stability of soil slopes will be covered with great detail under this course. The active pressure develops when the wall is free to move outward such as a typical retaining wall and the soil mass stretches sufficiently to mobilize its shear strength. Lecture1 shear strength of soils free download as powerpoint presentation. Part ii1 soil composition, index properties and soil classification pdf 1. Dec 30, 2016 civil engineering mcqs shear strength of soils notes pdf civil engineering notes %. The observational method or back analysis can be used to determine engineering properties of soil or rock in cases where slope failures occur, or where embankment settlement or excessive settlement of existing structures have been observed.
In ancient times soil reinforcement consisted of mixing straw with mud, reinforcing with woven reeds, and using branches and other plant material to improve strength and capacity to. The strength of a material is the greatest stress it can sustain. Shear strength of soil, direct shear test, merits and demerits, triaxial tests. B v s viswanadham, department of civil engineering, iit bombay. S hears trengthm obilization is constant that is, cf room the periphery to the center of the soil cylinder. Determination of soil conditions is the most important first phase of work for every type of civil engineering facility. Apr 19, 2016 strength of different materials steel tensile strength concrete compressive strength soil shear strength presence of pore water complex behavior 3. The existence of three phases in soils is very common in the nature therefore the degree. Civil engineering advanced geotechnical engineering nptel. Concept, shear strength parameters, coulombs law, shear strength of cohesive and noncohesive soils, twelve simple laboratory and field tests for determination of shear strength of soils.
When you complete this chapter, you should be able to. Soil derives its shearing strength from the following resistance due to interlocking of particles frictional resistance between the individual soil grains adhesion between soil particles or cohesion contents. For a partially saturated soil, the shear strength can be expressed as fredlundet al. The advanced soil mechanics 4th edition pdf free download file has been uploaded to our online repository for the safer downloading of the file. Shear strength of soil strength of materials infrastructure. There can be many factors that affect the shear strength of cohesive soils, such as the following. It is bit complex to understand, for stability of structure it has a prime importance. Advanced soil mechanics 4th edition pdf free download direct. Similarly to the compression behavior, the intrinsic concept can also be used to predict the undrained shear strength of the studied soil. Role of geotechnical properties of soil on civil engineering. Undrained shear strength of a soil is the shear strength w.
Lecture 7 on stressstrain relationship and shear strength of soils. One has to learn basic principle of geotechnical engineering through soil mechanics and it is a core course for civil engineering in every collegeuniversity across the globe. Shear strength of soil free download as powerpoint presentation. Department of civil engineering geotechnical engineering lab. Shearing strength of soils and its tests the constructor. Soil mechanics lectures, class notes, research manuals. Pdf change of shear strength in soft soil excavations.
At yielding, in an uniaxial test, the principal stresses are 1 s y. Soil properties are determined by both field and laboratory test. For design of structures like dams, earth retaining structures, foundation shear strength of soil is taken into consideration. Mechanics of consolidation, theory of one dimensional. Drained and undrained soil shear strength duration. The shear strength of the soil may be defined as the maximum resistance along the failure plane in soils per unit crosssectional area under the load application. The shear strength can be expressed consis tently in terms of effective stress. Shear strength of soil may be defined as the resistance to shearing stresses and a consequent tendency for shear deformation. The stability of a cut, the slope of an earth dam, the foundations of structures, the natural slopes of hillsides and other structures. Shear strength of pervious and impervious soils soils derive their strength from contact between particles capable of transmitting normal as well as shear forces. In the short term, we would use an undrained shear strength model to determine whether or not shear failure or a slope failure would occur. Rrb je 2019 cbt 2 exam lec 15 shear strength of soil part 1 civil engg shubham sir duration.
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