Transferring tunnel alignment down a shaft: choose the correct sequence of steps—(1) hang two or more plumb lines, (2) determine the bearing of the plumb plane, (3) suspend a 35 kg weight to each plumb line, and (4) immerse the weights in water buckets to damp movement.

Introduction / Context:Accurate transfer of alignment from surface to underground is achieved by plumbing down reference lines in a shaft and establishing a stable “plumb plane.” The order of operations must ensure that lines are hung, weighted, and sufficiently stabilized before precise angular observations are taken to set out headings below.

Given Data / Assumptions:

• Two or more plumb lines are used to define a vertical reference plane.
• Weights (≈ 35 kg) are attached to minimize sway.
• Immersion in water acts as a damper to further steady the plumb bobs.
• Final goal: determine the plumb plane bearing accurately for transferring the alignment.

Concept / Approach:Stability precedes measurement. Lines must first be hung (geometry established), then weighted (reduce oscillations), and only then should bearing observations be made. Water damping is often used after preliminary stabilization to maintain steadiness during prolonged observations or in drafty shafts.

Step-by-Step Solution:

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