Some Engineering Problems Of The Panama Canal In Their Relation To Geology And Topography

70 ENGINEERING PROBLEMS OF PANAMA CANAL. Table of slopes for different rocks at different depths. Depth of excavation. Designation of class of rock. Feet. Meters. A B C D E F G 33 10 50 on 10 40 on 10 30 on 10 20 on 10 12 on 10 7 on 10 5 on 10 6ö 20 41 on 10 33 on 10 25 on 10 17 on 10 10.3 on 10 6.1 on 10 4.2 on 10 98 30 36 on 10 28 on 10 21 on 10 15. 4 on 10 9. 3 on 10 5. 6 on 10 3.6 on 10 131 40 32 on 10 25 on 10 19 on 10 14.4 on 10 8. 6 on 10 5. 2 on 10 3. 2 on 10 164 50 29 on ]() 22 on 10 16 on 10 18. 5 on 10 8 on 10 4. 9 on 10 2. 8 on 10 197 60 26 on 10 19 on 10 14 on 10 12.7 on 10 7.5 on 10 4.6 on 10 2. 5 on 10 230 70 24 on 10 18 on 10 13 on 10 12 on 10 7. 2 on 10 4.4 on10 2. 2 on 10 262 80 23 on 10 16 on 10 12 on 10 11.4 on 10 6.8 on 10 4.2 on 10 2 on 10 295 90 21 on 10 15 on 10 11 on 10 10. 8 on 10 6. 5 on 10 4 on 10 1. 9 on 10 328 100 20 on 10 14 on 10 10 on 10 10. 2 on 10 5.2 on 10 3. 9 on 10 1.8 on 10 361 110 18 on 10 13 on 10 9.8 on 10 9.5 on 10 6 on 10 3. 8 on 10 1. 7 on 10 394 120 17 on 10 12.5 on 10 9. 3 on 10 8.7 on 10 5. 9 on 10 3.7 on 10 1.6 on 10 427 130 16 on 10 12 on 10 9 on 10 8 on 10 5. 8 on 10 3. 6 on 10 1.5 on 10 459 140 15 on 10 11.5 on 10 8. 8 on 10 7. 4 on 10 5.6 on 10 3. 5 on 10 492 150 j 14.5 on 10 11 on 10 8.6 on 10 6. 8 on 10 5. 5 on 10 3. 4 on 10 1.4 on 10 525 160 14 on 10 10. 8 on 10 8. 4 on 10 6. 5 on 10 5. 4 on 10 3. 3 on 10 558 170 13.5 on 10 10.5 on 10 8.3 on 10 6.3 on 10 5. 3 on 10 3. 2 on 10 1.3 on 10 591 180 13 on 10 10.3 on 10 8. 2 on 10 6. 2 on 10 5.2 on 10 3.1 on 10 623 190 12.5 on 10 10.1 on 10 8.1 on 10 6.1 on 10 5.1 on 10 3.05 on 10 656 200 12 on 10 1 10 on 10 8 on 10 6 on 10 5 on 10 3 on 10 1.2 onlO Note.—The slope given for each depth in the above table is to extend from the bottom to the top of the excavation at the same angle (plus hyperbolic curvature tangent to the slope and bottom, as already ex- plained). If an excavation is 200 meters deep in class A rocks, its slope is to be 12 on 10, plus curvature, from bottom to top, and not 50 on 10 for the first 10 meters, 41 on 10 for the second, and so on. Heavy blasting should not be used right up to the completed slopes if they are to stand at the angles given above. When ground once begins to deform, the angle at which it will stand will be much flatter than that at which it would have stood before movement set in. In any given excavation the weakest rock encountered will govern the slope for that excavation. BIBLIOGRAPHY ON SLIDES. The following bibliography, with a few additions by the author, is taken from a paper a by George S. Rice, chief mining engineer of the Bureau of Mines: Baumgarten, Karl. Thunder Mountain landslide. Min. and Sei. Press, vol. 101, Nov. 26, 1910, pp. G98-699. Canada, Department of Interior. Report on the great landslide at Frank, Al- berta. Annual Report, 1903, pt. 8, appendix to Rept. of Supt. of Mines, 17 pp. Canada, Department of Mines, Geological Survey Branch. Report of the com- mission appointed to investigate Turtle Mountain, Frank, Alberta, 1911, p. 34. Clarke, D. D. A phenomenal landslide. Trans. Am. Soc. Civ. Eng., vol. 53, December, 1904, pp. 322-412. Cornish, Vaughan. The Panama Canal and the philosophy of landslides. Edin- burgh Rev., vol. 217, January, 1913, pp. 21-42. Ells, II. W. Report on the landslide at Notre Dame de la Salette, Lievre River, Quebec. Canada, Department of Mines, Geological Survey Branch Publications, No. 1030, 1908, 10 pp. Engineering News. A novel method of stopping a landslide at Seattle, Wash. Vol. 31, May 10, 1894, p. 387. ------The slides on the Panama Canal. Vol. 65, May 11, 1911, pp. 570-573. Ford, F. L. The settlement of Loraine Street, Hartford, Conn. Eng. Record, vol. 45, Feb. 22, 1902, pp. 172-173. ° A suggested method of preventing rock slides. Discussion. Jour. West. Soc. Eng., vol. 18, No. 7 September, 1913, pp. 585-627.