Abstract
This is the study of the stability of treacherous clayey soil for the object to conduce to the consideration of the design of foundation and the fundamental principle of the soil stabilization. The mechanical properties of clayey soil were tested on the research materials of the undisturbed soil and the disturbed (remolded), and then the relative characters between both have been investigated particularly. Whereupon, in this paper, following matters are pointed out conclusivly. 1. The strength of disturbed soil must be discussed separately in the following both cases (a) & (b). (a) On the soil condition immediately after broken by sudden and dynamic load (such as driving of piles and seismic action, etc.). (b) On the soil conditions observed after slow and nondynamic phenomena of soil failures, or that passed long time after the occurrence of the case (a). Mechanical property of soils in the sase (a) can be assumed by the sensibility ratio S_t that Terzaghi or Tschebotarioff has defined. But on the condition of the case (b), following defined index [numerical formula] must be adopted, which is found out from the result of triaxial compression test by the testing method of the consolidated quick shear. [numerical formula] This revised sensibility ratio (named by author) can be expressed, by the graphic indication, from Fig. 2 (a). [numerical formula] 2. When the presure of constraint of the soil is over a limit range the revised sensibility ratio [numerical formula] become nearly constant value (more or less 1.0). (See Fig. 15) Ordinary the pressure value in this limited range is very small which seems to be between 0 and 0.5kg/cm^2 thereabout, though it is not so conclusively limited in this report yet. (Fig. 6,7,8) Assordingly, this fact means that if there is the stress of constraint over this limit value in the ground, shearing resistance of the disturbed soil does not reduce substantially when the disturbed ground has passed proper time after the disturbance. 3. When the stress of constraint is O, revised sensibility ratio [numerical formula] become equal to sensibility ratio [numerical formula] 4. We can make clear the some practical phenomena accompanied with the failure of clayey ground by this property of revised sensibility ratio. 5. One of the important theories concerned the design and construction of foundation on the treacherous cleayey ground is the forming the relative condition of ground and building so that revised sensibility ratio [numerical formula] is constant (≑1).
