Ch. 13] REFERENCES 243 



Methods of changing stress distribution include drainage to relieve 

 pore-water pressure, cutting back slopes and loading the toe of the 

 slide to decrease the moment of forces tending to produce sliding, and 

 the use of various types of barriers such as retaining walls, cribbing, 

 and piles. Small rockslides in dipping strata have been successfully 

 stopped by blocking or pinning loose slabs to the underlying firm rock 

 (Laurence, 1948). 



Much has been written about the remedial measures applicable to 

 landslides. The reader is referred especially to the works of Ladd 

 (1935), Hennes (1936), and Forbes (1946) ; to the Proceedings of the 

 First and Second International Conferences on Soil Mechanics and 

 Foundation Engineering; to papers that appear occasionally in the 

 Proceedings and Transactions of the American Society of Civil Engi- 

 neers; and to many short articles in Engineering News-Record. 



FUTURE RESEARCH 



The cure for landslides is frequently difficult and costly, and all too 

 often not completely satisfactory. Research in the problem of land- 

 sliding should be directed not only at devising new and better methods 

 of alleviating slides, but also increasingly toward developing criteria 

 for the recognition of potentially unstable areas. Much has been done 

 along this line in soil mechanics, especially in the criteria of stability 

 for more or less homogeneous clay. Much remains yet to be done in 

 the study of the natural fine structures of clays and silts, how they 

 develop, how and why they change with time, loading, and water 

 content, and the role of mineralogy and soluble salts on changes in 

 structure. 



It has become increasingly clear that the stability of earth materials 

 is a function of many factors, some of which are not easily recognized 

 or evaluated. If the rank and file of engineers and geologists can be- 

 come aware of the necessity for closer study of the slides they en- 

 counter, and if soil engineers continue their researches at the present 

 pace, perhaps sufficient data will become available to permit formula- 

 tion of general principles of slope stability, even for non-uniform 

 materials. 



REFERENCES 



Alden, W. C. (1928). Landslide and flood at Gros Ventre, Wyoming: Amer. Inst. 

 Min. Met. Engrs., Tech. Pub. 140; Trans., vol. 76, pp. 347-361; abstract, 

 Mining and Metallurgy, vol. 9, No. 262, p. 465, Oct. 1928. 



Anderson, Robert (1908). Earth flows at the time of the San Francisco earth- 

 quake: Bull. Geol. Soc. Amer., vol. 18, p. 643. 



