The dilatancy and non-coaxiality of sand are investigated under generalised loading including rotation of the stress principal axes (PA), in drained and undrained conditions. Weak non-coaxiality is exhibited under radial loading being dependent on the stress direction relative to the deposition direction, as well as on state, and gradually diminishing beyond peak failure. On the contrary, non-coaxiality is stronger and persists in the post-peak regime when sand is subjected to rotation of the stress PA. In conditions involving undrained rotation of the stress PA at constant total stress principal values (PV), distinct non-coaxiality patterns and elastic–plastic coupling are observed under increasing stress ratio, while a steady state is ultimately attained. This study shows that sand exhibits strong non-coaxiality and contracts immediately upon initiating the rotation of the stress PA at constant effective stress PV very close to critical state (CS), while it was previously dilating on the failure surface in a coaxial deformation mode, under radial loading; the phenomenon becomes increasingly intense as CS is approached. The degree of non-coaxiality and associated contractancy becomes higher when the previous shearing becomes more persistent, in terms of shear strain accumulation, while the influence of pre-shearing is stronger than that of the degree of stress rotation and the level of η = q/p′, p′, e, and b = (σ′₂ − σ′₃)/(σ′₁ − σ′₃), but diminishes gradually during stress rotation.

在排水和不排水条件下，在包括应力主轴（PA）旋转在内的一般载荷下研究了砂的膨胀性和非同轴性。在径向载荷下表现出弱的非同轴性，径向载荷取决于相对于沉积方向的应力方向以及状态，并逐渐减小到超过峰值破坏。相反，当砂子受到应力PA的旋转时，非同轴性更强，并在峰后状态中持续存在。在恒定总总应力主值（PV）下应力PA不排水旋转的情况下，在应力比增加的情况下观察到明显的非同轴度模式和弹塑性耦合，同时最终达到了稳态。这项研究表明，砂表现出很强的非同轴性，并且在非常接近临界状态（CS）的恒定有效应力PV上启动应力PA旋转时，砂会立即收缩，而砂以前曾以同轴变形模式在破坏面上膨胀，在径向载荷下 随着接近CS，现象变得越来越严重。就剪切应变累积而言，当先前的剪切变得更加持久时，非同轴度和相关的收缩度会变得更高，而预剪切的影响要比应力旋转的程度和水平的影响要大。随着接近CS，现象变得越来越严重。就剪切应变累积而言，当先前的剪切变得更加持久时，非同轴度和相关的收缩度会变得更高，而预剪切的影响要比应力旋转的程度和水平的影响要大。随着接近CS，现象变得越来越严重。就剪切应变累积而言，当先前的剪切变得更加持久时，非同轴度和相关的收缩度会变得更高，而预剪切的影响要比应力旋转的程度和水平的影响要大。η  =  q / p '，P' ，ê，和b  =（σ' ₂  -  σ' ₃）/（σ' ₁  -  σ ' ₃），但应力在旋转期间逐渐减小。