下面雅思与大家分享一篇地理方面的雅思阅读模拟真题材料,主要内容是很多公司在施工的时候经常会对各种已经有的设施和结构进行相关的处理。那么这样做需要有什么准备吗?需要通过什么步骤来实施呢?下面就是相关信息。
Geophysics For Utility Location: When It Works - When It Wont
Utility companies, construction projects, and highway contractors are often faced with the need to excavate or pipe-jack in the vicinity of known or suspected buried utility lines, drains, or other subsurface structures. In many cases, particularly where they are adjacent to highways, the lateral position of the lines may be documented with reasonable accuracy, but the vertical position, or burial depth, may be uncertain due to changes in grade caused by construction or maintenance performed after the pipes were buried.
One way to verify the location of such buried objects is to cautiously dig a trial pit to expose the object in question. However, digging such a pit in or close to a highway is costly because of the need for traffic control, and subsequent reinstatement of the surface to meet the original specification. There is also a substantial risk of accident and personal injury, partly due to the disruption caused to the highway traffic, and partly due to the nature of the work. Where mechanical digging equipment is used, an undocumented or misaligned utility line can easily be damaged if the excavation workers do not observe it. Gas and electricity lines present very obvious safety threats in this situation.
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