A. The topographical maps of the Survey of India are useful in the mountainous region for tunnelling.
B. The height point on the ridge is fixed with the help of reciprocal ranging
C. The accuracy of 1 in 10, 000 is required for planimetric control
D. 1 second theodolite is used for angular measurement to achieve an angular error of 15 N where N is number of angles
E. All the above.
Correct Answer
All the above.
Tunnelling problems
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1. The following operations are required for tunnelling in rocky terrain : 1. Removing the foul gases 2. Marking the tunnel profile 3. Setting up and drilling 4. Checking misfire 5. Mucking The correct sequence is :
10. For transferring the tunnel alignment through shafts, we adopt the following steps : 1. Hanging two or more plumb lines in the shaft 2. Determining the bearing of the plumb lines i.e. plumb plane 3. Suspending a 35 kg weight by each plumb line 4. Immersing the weights of both the plumb lines in the buckets containing water. The correct sequence of steps is :