【正文】 os )T W k???? （ 4） where is the inclination of the failure surface and w is given by 02( ta n ta n ) ( ta n )( c o t c o t )2LW x x d x H x d xH? ? ? ? ?? ??? ? ? ????? （ 5） where ? is the unit weight of soil, H the height of slope, c ot , c ot ,L H l H? ? ??? is the inclination of the slope. Since the length of the slide surface AB is /sincH ? , the resisting force produced by cohesion is cH/sin a. The friction force produced by N is (c os si n ) ta nWk? ? ?? . The total resisting or antisliding force is thus given by ( c os si n ) t a n / si nR W k c H? ? ? ?? ? ? （ 6） For stability, the downslope slide force 185。s rigorous method5 introduces a further numerical procedure to permit specialcation of interslice shear forces Xl and Xr . SinceXl and Xr are internal forces, ()lrXX?? must be zero for the whole section. Resolving prerpendicularly and parallel to EF, one gets sin c osT hd x k hd x? ? ? ??? （ 9） c os c si nN hd x k hd x? ? ? ??? （ 10） 22a r c sin ,xa r a br? ?? ? ? （ 11） The force N can produce a maximum shearing resistance when failure occurs: se c ( c os si n ) t a nR c dx hdx k? ? ? ? ?? ? ? （ 12） The equations of lines AC, CB, and ABY are given by y 221 2 3ta n , , ( )y x y h y b r x a?? ? ? ? ? ? （ 13） The sums of the disturbing and resisting moments for all slices can be written as 01 3 2 30( si n c o s )( ) ( si n c o s ) ( ) ( si n c o s )()lsllLscM r h k d xr y y k d x r y y k d xr I k I? ? ?? ? ? ? ? ????? ? ? ? ? ?????? (14) ? ?02300232sec ( c os si n ) t a nsec ( ) ( c os si n ) t a n( ) ( c os si n ) t a nt a n ( )lrlllLcsM r c h k dxr c dx r y y k dxr y y k dxr c r I k I? ? ? ? ?? ? ? ? ?? ? ? ?? ? ?? ? ?? ? ? ?? ? ?? ? ????? (15) 22c o t , ( )L H l a r b H?? ? ? ? ? （ 16） a r c si n a r c si nl a arr? ??? （ 17） 1 3 2 3022( ) sin ( ) sin1( c o t ) se c23Lls LI y y d x y y d xH a b Hr????? ? ? ???? ? ??????? （ 18） 1 3 2 30222 2 2 22 2 2( ) c os ( ) c ost a n t a n2 ( ) ( ) ( )6 2 3( t a n ) a r c si n ( t a n ) a r c si n221( ) a r c si n( ) 4 ( ) ( )26Lls LI y y dx y y dxb r br L a r L arrr L a r aa H a brrr l ab H r l ab l a H arr????? ? ? ???? ? ? ? ? ? ? ????? ? ? ?? ? ? ?? ? ? ?? ? ? ????? ? ? ? ? ? ??? （ 19） The safety factor for this case is usually expressed as the ratio of the maximum available resisting moment to the disturbing moment, that is ta n ( )() csrs s s cc r I k IMF M I k I? ? ?????? ? (20) When the slope inclination exceeds 543, all failures emerge at the toe of the slope, which is called toe failure, as shown in Figure 2. However, when the slope heightH is relatively large pared with the undrained shear strength or when a hard stratum is under the top of the slope of clayey soil with 03?? , the slide emerges from the face of the slope, which is called Face failure, as shown in Figure 3. For Face failure, the safety factor Fs is the same as 185。39。cI are given by ? ? ? ? ? ?010039。s method avoids a buildup of linear dependence. The closedform slope stability equation (21) allows the application of an optimization technique to locate the center of the sliding circle (a, b). The minimum factor of safety Fs min then obtained by substituting the values of these parameters into equations (22)~(25) and the results into equation (21), for a base failure problem (Figure 4). While using the Powell39。s method, the results obtained from each of those three methods are listed in Table I. The cases are chosen from the toe failure in a hypothetical homogeneous dry soil slope having a unit weight of kN/m3. Two slope configurations were analysed, one 1 : 1 slope and one 2 : 1 slope. Each slope height H was arbitrarily chosen as 8 m. To evaluate the sensitivity of strength parameters on slope stability, cohesion ranging from 5 to 30 kPa and friction angles ranging from 103 to 203 were used in the analyses (Table I). A number of critical binations of c and were found to be unstable for the model slopes studied. The factors of safety obtained by the proposed method are in good agreement with those determined by the local minimum factorofsafety and Bishop39。 the friction angle is 。, Geotechnique, 5, 7}17 (1955). 6. K. E. Petterson. amp。 J. Soil Mech. Found, ASCE, 99(7), 495}507 (1973). 8. Y. Kohgo and T. Yamashita, amp。, J. Geotech. Engng. ASCE, 122(7), 577}596 (1996). 10. V. U. Nguyen. amp。 Can. Geotech. J., 20(1), 104}119 (1988). 12. W. F. Chen and X. L. Liu. 184。Practical examples of the /0 analysis of stability of clays39。Longterm stability of clay slopes,39。Determination of critical slip surface in slope stability putations39。ondon, 36(1), 57}64 (1986). 23. B. M. Das. Principles of Soil Dynamics, PWSKent Publishing Company, Boston, 1993. 24. S. L. Huang and K. Yamasaki. amp。, J. Geotech. Engng. ASCE, 118(11), 1748}1764 (1992). 27. K. S. Li and W. White. amp。 地震 被認為是用 和振動 相似的方式產(chǎn)生的地震從屬效應。推薦的方法是基于最危險滑動面的直接的，最簡單的去用并且最快的計算，和計算該斜坡的最小安全系數(shù)。動力學因素 。直到 1840年，英國和法國的鐵路和隧道的鉆鑿和路堤經(jīng)驗表明了許多泥土中的破壞面不是平的，而是沒有規(guī)律 的彎曲的。到十九世紀五十年代中期，人們的注意力轉(zhuǎn)移到了用圓形和非圓形滑動面的分析上了。 定位的滑動面具有最低的安全系數(shù)的分析 ,是一個邊坡穩(wěn)定問題重要的一部分。 承擔合理的滑動面是 斯潘塞 (1969)發(fā)現(xiàn)考慮的 圓形滑移面和對數(shù)螺旋滑動面是同樣臨界的使用目的。地應力是幾乎 按照地震系數(shù)定義的慣性力來估計的。 在此研究中圓形滑動面是用于粘土質(zhì)斜坡分析框架內(nèi)的一個 。平緩的滑動面用來分析砂性 的斜坡。39。39。39。 穩(wěn)定性分析包括解決涉及力和力矩平衡的問題。在一些重要的二維滑坡的應用是可以應用的。把滑動體 ABC 上的平衡力豎向分解，作用在滑動體上的垂直力一定是平衡與滑動體的自重 W的。安全因素 sF 可以由 R和 T的比例來確定，也就是： 1 ta n 2ta nta n ( s in c o s ) s in ( )