Slope Failure

              Mass Wasting or Slope Failure 

   

After reading this article , you should be able to :

• Explain how slope stability is related to slope angle 
• Summarize some of the factors that influence the strength  of material on slopes, including types of rock, presence  and orientation of planes of weakness such as bedding or fracture , type of unconsolidated material and the effect of water
• summarize the type of motions that can happen during mass Wasting 

     

 

Early in the morning on Jan 9, 1965 , 47 million cubic meters of rock broke away from the steep upper slope of johnson Peak and roared 2000 m down the mountain,  which is shown in above figure . four people who have been stooped on the highway by a snow avalanche were killed.

Mass Wasting is synonymous with " slop failure " is the failure and downslope movement of rock or unconsolidated material in the response to gravity.

the term ' land slide' is almost synonymous with mass wasting , but not quite because some people reserve " land slide " for relatively rapid slope failures , while other do not .

# Factors that controls slope stability

1. The Angle of  The Slope 
2. The Strength of The Material On It

         

        

The above shows the difference in the shear and normal component of gravitational force on slopes with differing steepness. The gravitational force is same in all the three cases.
           In ( a ) the shear force is simultaneously less than the shear strength , so the block should be stable.
           In ( b ) the shear force is and shear strength are  about equal , so the block may or may not move .
           In ( c ) the shear force is subsequently greater than the shear strength so , the block is very quickly to move.

  Classification of Mass Wasting 

here we show a table which classifies all type of slope failure and its properties such as type of material , type of motion , Rate of motion.

so the above table tell every thing about different types of slope failure.

        Now , i show you some figure of diffrent types of failure.

1. Rock Fall

                  
    in rock fall , the contribution of  freeze - thaw to rock fall.
this is known as talus slope.

this above figure shows a talus slope near 

Keremos, B. C. , formed by rock fall from the cliff above in the left side. 

and , in right side : the result of a rock fall onto a highway west of Keremos in December 2014.

2. Rock Slide

 The downie slide , a sackung on the shore of the Revelstoke Reservoir ( above the Revelstoke Dam). The head scrap is visible at the top and a slide - scrap along the left side.