Những khoáng chất này thường được tạo bởi từ các nguyên tử của các nguyên tố phổ biến như ôxy, silic, hydro, và nhôm, chúng tạo thành nhiều dạng tinh thể khác nhau. | 128 Using the numerical values of K Ằ M p0 already quoted we get the curves of Fig. where the points corresponding to total distortion of 1 2 3 4 and 8 per cent are clearly marked. In comparison we can reason that relatively larger strains will occur at each stage of a drained test. In Fig. a we consider both drained and undrained compression tests when they have reached the same stress ratio n 0. From eq. we have vp v M - n 8 8 0 vv so that in each test there will be the same shift of swelling line vK for the same increment of distortion 8. The yield curves relevant to the successive shifts of swelling line are lightly sketched in Fig. a . We see the undrained test slanting across them from U1 to U2 while the drained test goes more directly from D1 to D2. It follows that for the same increment of distortion 8 there will be a greater increment of n in an undrained test than in a drained test which explains the different curves of q p versus 8 in Fig. b . Fig. Predicted Strain Curves for Undrained Axial Compression Test of Fig. For the undrained test differentiating eq. we get Ati m - p q which equals the plastic volume change vKlV0 since v 0 and hence we have eq. . For the drained test differentiating eq. we get n MIẦ - k v - ÀpỊp and since qỊp 3 we also have n qỊp - qpp 3 - n p p 3 - n v - vK . Eliminating p and v we obtain eq. . 129 We can in fact derive expressions for these quantities. It can readily be shown that for the increment U1U2 in the undrained test kA Mn M -nXArndrarned v V0 whereas for D1D2 in the drained test m M 3-n n M - n v0 drained where v varies as the test progresses and is v0 . Fig. Relative Strains in Undrained and Drained Tests Hence the ratio of distortional strains required for the same increment of n is ẻd w -n M v0 7 7 ẻu K 3 -n vd and we shall expect for specimens of remoulded London clay a at the start of a pair of tests when n 01 1 A. vd vo J and b by the end when
