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Geokon 4300 Series, Инструкция по эксплуатации

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Geokon 4300 Series Скачать руководство пользователя страница 12

6 

2.6 Splicing and Junction Boxes 

 

Because the vibrating wire output signal is a frequency rather than a current or voltage, 

variations in cable resistance have little effect on gauge readings. Therefore, splicing of cables 

has no effect, and in some cases may in fact be beneficial. For example, if multiple stressmeters 

are installed in a borehole, and the distance from the borehole to the terminal box or datalogger is 

great, a splice (or junction box) could be made to connect the individual cables to a single multi-

conductor cable. This multi-conductor cable would then be run to the readout station. For these 

types of installations, it is recommended that the stressmeter be supplied with enough cable to 

reach the installation depth, plus extra cable to pass through drilling equipment (rods, casing, 

etc.). 

 

Cable used for making splices should be a high quality twisted pair type, with 100% shielding 

and an integral shield drain wire. 

When splicing, it is very important that the shield drain 

wires be spliced together.

 Splice kits recommended by Geokon incorporate casts that are placed 

around the splice and then filled with epoxy to waterproof the connections. When properly made, 

this type of splice is equal or superior to the cable in strength and electrical properties. Contact 

Geokon for splicing materials and additional cable splicing instructions. 

  

Junction boxes and terminal boxes are available from Geokon for all types of applications. In 

addition, portable readouts and dataloggers are also available. Contact Geokon for specific 

application information. 

 

 

Содержание 4300 Series

Страница 1: ...ed by any means without the written consent of Geokon The information contained herein is believed to be accurate and reliable However Geokon assumes no responsibility for errors omissions or misinterpretation The information herein is subject to change without notification Copyright 1984 2019 by Geokon Doc Rev I 1 09 2019 ...

Страница 2: ......

Страница 3: ...nnel There are no warranties except as stated herein There are no other warranties expressed or implied including but not limited to the implied warranties of merchantability and of fitness for a particular purpose Geokon is not responsible for any damages or losses caused to other equipment whether direct indirect incidental special or consequential which the purchaser may experience as a result ...

Страница 4: ......

Страница 5: ... with Bare Leads 8 3 2 3 Operating the GK 405 8 3 3 GK 403 READOUT BOX OBSOLETE MODEL 9 3 3 1 Connecting Sensors with 10 pin Bulkhead Connectors Attached 9 3 3 2 Connecting Sensors with Bare Leads 9 3 3 3 Operating the GK 403 9 3 4 MEASURING TEMPERATURES 9 4 DATA REDUCTION 10 4 1 CHANGE IN STRESS CALCULATION 10 4 2 ENVIRONMENTAL FACTORS 10 4 3 GAUGE SENSITIVITY FACTORS 11 4 4 CORRECTIONS FOR TEMPE...

Страница 6: ... ROCK MODULUS 11 FIGURE 7 MODEL 4300NX SENSITIVITY FACTOR VS ROCK MODULUS 12 TABLES TABLE 1 SAMPLE CALCULATIONS 10 TABLE 2 SAMPLE RESISTANCE 14 TABLE 3 RESISTANCE WORK SHEET 14 TABLE 4 SPECIFICATIONS 15 TABLE 5 THERMISTOR RESISTANCE VERSUS TEMPERATURE 16 EQUATIONS EQUATION 1 CHANGE IN STRESS 10 EQUATION 2 TEMPERATURE CORRECTION 12 EQUATION 3 RESISTANCE TO TEMPERATURE 16 EQUATION 4 PLANE STRESS 17 ...

Страница 7: ...g is largely indeterminate and the indicated stress magnitude can only be approximate A coil and magnet assembly located close to the wire is used to both excite the wire and sense the resultant frequency of vibration When the gauge is connected a pulse of varying frequency is applied to the coil and magnet assembly and this causes the wire to vibrate at its resonant frequency The wire continues t...

Страница 8: ...s gives the gauge a very high range and since as the load increases the wire gets tighter the wire never goes slack Gauge installation is accomplished by driving a wedge between the gauge body and the platen which contacts the borehole walls Preloading to desired levels is accomplished by further driving of the wedge with the setting tool In soft rocks a soft rock platen and soft rock shoe are use...

Страница 9: ...he standard wedge and platen assembly Model 4300NX Stressmeters are designed for use in NX diamond drill holes 76 mm 2 98 and the hole can range in diameter from 75 mm 2 95 to 77 5 mm 3 05 when using the standard wedge and platen assembly Oversize platens are available for oversize boreholes consult factory 2 2 Preliminary Checks Before installing the gauges in the field perform a preliminary chec...

Страница 10: ...gh the slot in the setting head See Figure 2 below Connect the first section of 1 4 rod to the yoke attached to the thin end of the wedge Note that the first section of rod has one end with a 20 left handed thread on it This will connect to the left handed thread in the yoke Attach the first section of the 3 4 positioning rod to the back of the setting tool head Push the stressmeter into the hole ...

Страница 11: ... subsequent gauges are pushed into the hole If necessary after setting the gauges and obtaining the final readings push the leads back into the borehole and seal the borehole using an expandable rockbolt anchor or a short bolt This will discourage vandalism if this is a problem Note that the stressmeter initial readings will probably diminish slightly over the first day or two as the instrument be...

Страница 12: ...plied with enough cable to reach the installation depth plus extra cable to pass through drilling equipment rods casing etc Cable used for making splices should be a high quality twisted pair type with 100 shielding and an integral shield drain wire When splicing it is very important that the shield drain wires be spliced together Splice kits recommended by Geokon incorporate casts that are placed...

Страница 13: ...epresenting the shield bare To turn the GK 404 on press the ON OFF button on the front panel of the unit The initial startup screen will be displayed After approximately one second the GK 404 will start taking readings and display them based on the settings of the POS and MODE buttons The unit display from left to right is as follows The current Position Set by the POS button displayed as a letter...

Страница 14: ...nto place 3 2 2 Sensors with Bare Leads Attach the GK 403 2 flying leads to the bare leads of a Geokon vibrating wire sensor by connecting each of the clips on the leads to the matching colors of the sensor conductors with blue representing the shield bare 3 2 3 Operating the GK 405 Press the button labeled POWER ON BLUETOOTH A blue light will begin blinking signifying that the Remote Module is wa...

Страница 15: ...ire output in digits The last digit may change one or two digits while reading 4 The thermistor reading will be displayed above the gauge reading in degrees centigrade 5 Press the Store button to record the value displayed If the no reading displays or the reading is unstable see Section 5 for troubleshooting suggestions The unit will automatically turn off after approximately two minutes to conse...

Страница 16: ...ibration using a 6 144 MHz quartz oscillator and displays the period to a resolution of 0 1 microseconds in position A Positions F and B are used for stressmeters the processor converts the period readings to units of frequency squared which is proportional to wire strain gauge deflection and applied stress A reading of 10 000 on channel F corresponds to a period of 316 2 microseconds on channel A...

Страница 17: ...erent moduli Sensitivity factors are based on experimental data conducted on rock samples and can only serve as a guide For more accurate determinations of stress sensitivity calibrations must be performed in samples of the rock being monitored Figure 5 Model 4300EX Sensitivity Factor vs Rock Modulus Figure 6 Model 4300BX Sensitivity Factor vs Rock Modulus ...

Страница 18: ...rise Stress correction for temperature is given by the equation σT R1 R0 G T1 T0 2G Equation 2 Temperature Correction Where σT The stress change corrected for temperature R0 Initial reading after the gauge has been set in place R1 Reading at subsequent stress T0 Initial temperature C T1 Subsequent temperature C G Sensitivity factor taken from Section 4 3 It should be noted that this temperature co...

Страница 19: ...ngs automatically are the swept frequency excitation settings correct Is there a source of electrical noise nearby Likely candidates are generators motors arc welding equipment high voltage lines etc If possible move the instrument cable away from power lines and electrical equipment or install electronic filtering Make sure the shield drain wire is connected to ground Connect the shield drain wir...

Страница 20: ...X 180Ω EX 90Ω N A infinite infinite infinite White infinite infinite N A 3000Ω at 25 C infinite Green infinite infinite 3000Ω at 25 C N A infinite Shield infinite infinite infinite infinite N A Table 2 Sample Resistance Vibrating Wire Sensor Lead Grid SENSOR NAME Red Black White Green Shield Red Black White Green Shield Table 3 Resistance Work Sheet ...

Страница 21: ...5 Weight kgm lbs 0 45 1 0 9 2 1 4 3 Borehole Diameter mm inches 38 1 485 60 2 36 76 2 98 Gauge Material Stainless Steel Cable Two conductor or four conductor 22 gauge shielded PVC jacket 5 mm or 6 mm dia Table 4 Specifications Notes 1 Depends on rock modulus 2 Accuracy depends to a large extent on the roughness of the borehole walls gauge stiffness and on the degree to which the platens bed into t...

Страница 22: ...2 83 107 9 123 77 66K 36 8006 4 1363 44 331 5 84 105 2 124 72 81K 35 7618 5 1310 45 321 2 85 102 5 125 68 30K 34 7252 6 1260 46 311 3 86 99 9 126 64 09K 33 6905 7 1212 47 301 7 87 97 3 127 60 17K 32 6576 8 1167 48 292 4 88 94 9 128 56 51K 31 6265 9 1123 49 283 5 89 92 5 129 53 10K 30 5971 10 1081 50 274 9 90 90 2 130 49 91K 29 5692 11 1040 51 266 6 91 87 9 131 46 94K 28 5427 12 1002 52 258 6 92 85...

Страница 23: ...ng the relationship between the rock modulus and the gauge modulus Hast 1958 has shown this to be applicable for a uniaxial stressmeter For the measurement of stress σR in any direction θ the following equation applies Note θ is measured counterclockwise from σ1 σR 1 3 σ1 σ2 2 3 σ1 σ2 cos 2 θ Equation 5 Stress in any Direction Using this relationship and three uniaxial stress change measurements a...

Страница 24: ...uge 1 σ0 600 psi Gauge 2 σ45 800 psi Gauge 3 σ90 300 psi Calculate the values for constants a and b a σ0 σ90 2 600 300 2 450 b σ45 a 2 σ0 a 2 1 2 800 450 2 600 450 2 1 2 380 79 σ1 3 2a 3 4b 3 x 450 2 3 x 380 79 4 960 59 psi σ2 3 2a 3 4b 3 x 450 2 3 x 380 79 4 389 41 psi sin 2θ 0 92 θ 33 40 σ1 Direction since σ45 a and σ0 σ90 then 135 θ 180 Therefore θ 180 33 40 146 6 This is measured clockwise fro...

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