<p> (1)土的极限平衡条件:<img src="http://que-oss.fenziquan.com/web/akimg/asource/2014091814191530590.jpg">即<br> <img src="http://que-oss.fenziquan.com/web/akimg/asource/2014091814194982950.jpg"><br> 土处于极限平衡状态时破坏面与大主应力作用面间的夹角为,且<img src="http://que-oss.fenziquan.com/web/akimg/asource/2014091814203033734.jpg"><br> (2)当为无粘性土(c=0)时,或<img src="http://que-oss.fenziquan.com/web/akimg/asource/2014091814210465997.jpg"></p>