SafetyCâu 103 / 110
A trench 10 ft deep in Type B soil is sloped at 1 to 1 (horizontal to vertical) on both sides. If the trench bottom is 3 ft wide, how wide is the excavation at the top?
a.13 ft
b.20 ft
c.23 ft
d.30 ft
Giải thích
Each side slopes back 1 x depth = 10 ft, so the top width = bottom + 2 x 10 = 3 + 20 = 23 ft. Type B soil requires a 1-to-1 slope, while less stable Type C requires 1.5 to 1 and would open even wider. The soil classification set by a competent person drives the excavation width and spoil space needed.
Trích dẫn luật: 29 CFR 1926.652Luyện miễn phí toàn bộ 110 câu hỏi — không cần đăng ký.
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