|
"Response of Pressurized Pipelines to purposes unrelated CO the pipeline study.
<br /> Production--Sipe Mine Blasting" In front of the pipeline, AMAX had installed
<br /> continued from page 22 both coaxial and fiberopdc phone cables, and also
<br /> had a vertical well off the east end of the 6-in
<br /> PROCEDURES pipeline. The well, of about 120-ft depth, was
<br /> Pipelines instrumented for pressure by Vibronics. It was test-
<br /> Five 250-ft-long sections of transmission ed for cement bond log on three occasions: prior to
<br /> pipeline, with properties described in table 1, were blasting, after 4in/s and after 9 in/s. No significant
<br /> installed on the AMAX Coal Company's Minnehaha bond loss was noted. The phone lines were tested
<br /> Mine highwall for testing to destruction. They were by Indiana Bell and will be reported separately.
<br /> all parallel to each other with 10-ft spacings and RESULTS
<br /> also to the highwall at an initial distance of about 500 Between the Bureau and Vibronics,about 34 data
<br /> channels were used for each blast. A comprehen-
<br /> 7 able 1. Pipeline Information for Study sive future report will list all measurements; how-
<br /> 041404. Y411 $111 a4I21°� ,�°,°, ever, only highlights are presented in this paper.
<br /> 4t7154pr, 'nleknas2, uNr141 °16/10` , Weld Table 3 lists the highest me cared ground vibra-
<br /> 1° 14✓In
<br /> ` 1111` eons,
<br /> 4-5/11 .103 Cu 900 ll.r, 4t„a,449 - pipeline vibration responses and strains for
<br /> 794/1 .930 a
<br /> each blast. Figure 4 shows a set of vibration and
<br /> u 904 1.14e4. se„1. Cl 431 1
<br /> 19.3/4 .990 k, 904 /W n4411, t42 strain records from blast No. 25. Note that the
<br /> 991 Wt4r 9oa 1404. 440, 496 strains resemble vibration records, cycling nearly
<br /> 339' alter 90 um INC symmetrically about the zero line. Therefore, ten-
<br /> 4a4et pr45tt40 44144. sion and compression amplitudes were about equal.
<br /> -
<br /> ft as shown in figure 1. The location, in increasing
<br /> Table 2. Blasts monitored for pipeline response
<br /> distance from the highwall, are as listed in table 1. °~"r 061e '1s a6r44»1044. 114 4 16ec.. kilo.Distant, 5 ,,
<br /> Ohio Valley Pipeline welded and installed the 'Or"'u 6r• . ';"`
<br /> pipelines, using their standard procedures, after the I I:„ 114 IITI 11 1119 „t ;` °,rt,�
<br /> Bureau attached longitudinal and circumferential 7 7.20 1771 11.11' ' t'° I='400 4'7 a r. ,l
<br /> . 140 2343 97.60° 549 1q0 16.4 144 Plrtln5
<br /> 44 97:14 'Lai 1.291 1474 70.2 to Portia
<br /> strain gages and sensors for vibrations in the center 4.7 13144 47.144 1.454 070 74.3 90.0 Or.r04rao
<br /> area of the pipelines. All pipelines had longitudinal :;2 14:.0 91.641 440 7,64 144 772 P.nbq
<br /> 29 11111 31.2!1 1.171 7100 40.9 241 Amin
<br /> strain gages on tops and fronts and the 6- and 20-in '_ "::1 »:111 �" 24g ":� 029 ►;,11„"
<br /> had circumferential as well. Vibration transducers ' 4.1 97:97 44.794 3.,04 444 ,2.° 63.4 Or4rwr0.n
<br /> 1 1.t 111p t0,514 1.70 410 617 74,7 Owmura.n
<br /> were also placed on the tops and fronts of the 6- 3 4'4 11121 14.711 416 4014 II. 209 ''7'144
<br /> 4 U9 24:0° 97.154 390 312° 111 925 ►,'I,,,4
<br /> and 20-in pipes. Other, vibrations sensors were 4 4.1 97:20 44.472 1714 .34 11.6 7,.3 4„,41,,414
<br /> I1 4.14 °5123 32.442 1.114 970 44.5 Ill Or•rwr4m
<br /> 1:I It:11 Mlle 1.434 134 77.7 in r.r ..
<br /> place on the surface above the buried 20-in 4 4.4 92,3 33,'111 UPI 1 6O 41:1 III 'On/aj
<br /> pipeline. Following installations and the placement 20 4.1 MN 54.941 ions t7o 5.22 16a e...ane,4
<br /> of 3-ft of soil cover, the pipelines were internally ,, t.1 �l ll 413 4 1.141 Ill 1.41 Io.1 a,.�
<br /> 23 4.14 11104 70.234 1.124 224 O.. 97.1 0..r1,60..
<br /> pressurized. Pressures gradually crept up in steel 1! iii 713" 47:954 1.144 Iii 3.56 1i:4 pit:a',.4
<br /> Oir
<br /> pipelines to 950-1230 lb/in' as the ground warmed t5 4•I° 1..19
<br /> 17 7.31 3445 O,rasa,.
<br /> up from early spring to summer. It dropped in the I, 14.11 n. .. •• -- .. .. "47".4..
<br /> 44 C..r4.r4.n
<br /> PVC to 40123/in'in the following months consistent 14.24 10157 110 O..r°.ro.n
<br /> Ow.e4rn.n
<br /> with reports that such o-ring-jointed water pipes ''""'�ii Iron el 04 Pros 3.14..n.,,uo.eo'1641,In tI,.�x 011,1 '.p ne1•L,I t"
<br /> leak continuously. Note: Figure 1 does not show Vibrations
<br /> blasts 26 through 30, done too late to be included.
<br /> Mine Vibration amplitudes on the buried pipelines
<br /> were less than corresponding R and V components
<br /> The Minnehaha Mine is a surface coal mine, blast- measured on the ground directly above (shallow
<br /> ing overburden by casting and also a thick parting burial). This consistent and significant reduction of
<br /> using hole diameters of 12-1/4 and 10-5/8-in, about 40 pet at a depth of only 3-4 ft was surpris-
<br /> respectively.Charge weights per delay are as high as Ing, however, it is entirely in agreement with other
<br /> 2,100 lbs. The highwall, including the pipeline field studies including Bureau of Mines RI 8969 (Ref. 8),
<br /> area, has about 7 ft of clayey soil over-laying about which examined the effects of vibration monitoring
<br /> 40 ft of shale. on basement walls and floors. Figure 5 summarizes
<br /> Monitoring the surface radial vibration component and corre-
<br /> Strains and ground and pipeline vibrations mea- sponding horizontal response of the 20-in pipeline.
<br /> cured by the authors from selected parting blasts and Vertical vibrations behaved similarly
<br /> all nearly overburden blasts are presented in table 2. vibration frequencies of some blasts were low
<br /> In addition, Vibronics Inc. continuously monitored for the relatively small distances. As shown in fig-
<br /> both surface and underground vibrations at several care 4, the radial component of shot No. 25 is about
<br /> locations as well as pipeline pressures. AMAX and 5.6 Hz. This is ossib!
<br /> the IDNR also had blasting monitors in the area for p y a she phenomenon cased the clay layer over the shale.
<br /> 1 34
<br />
|