某公路选线时发现某段路基附近有一溶洞,溶洞顶板厚度为10m,岩层上覆土层厚度为6m,顶板岩体内摩擦角为28°,对一级公路安全系数取1.25,该路基与溶洞间的最小安全距离为()m。()
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
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