【填空题】151 / 251放坡挖沟槽常用V=(B+2c+kH)HL+(B+2c)hLV=(B+2c+kH)HL+(B+2c)hLV=(B+2c+kH)HL+(B+2c)hL,其中kkk表示____。参考答案暂无参考解析放坡系数。