DOI1.11779/CJGE14515 C-DTS C-DTS C-DTS T t T t w DTS DTS TU441.3 A 14548(14)5916 (1988 )E-mail: caodigfeg1@163.com Distributed method for measurig moisture cotet of soils based o C-DTS CAO Dig-feg 1, SHI Bi 1, YAN Ju-fa 1, WEI Guag-qig (1. School of Earth Scieces ad Egieerig, Najig Uiversity, Najig 146, Chia;. Suzhou NaZee Sesig Techology Co., Ltd., Suzhou 1513, Chia) Abstract: Based o the carbo-fiber-heatig-cable distributed temperature sesig system (C-DTS), a ew distributed method for measurig the moisture cotet of soils is proposed. The temperature of soil-buried-cable is measured by C-DTS i this method. The moisture cotet of soils is determied by the relatioship betwee the temperature characteristic value (T t ) ad the moisture cotet. T t is defied, ad it is proved that there is a liear relatioship betwee the moisture cotet ad T t. The relevat parameters ca be determied by calibratio experimet. The experimetal results show that the moisture cotet of soils ca be measured effectively through artificial heatig carbo-fiber-cable, ad the usage of DTS provides distributed measuremet. The accuracy of this method is related to the sectio of T t. The success of the proposed method provides a very advaced distributed approach for measurig the moisture cotet of soils. Further improvemet ad popularizatio are required. Key words: soil; moisture cotet; DTS; carbo fiber heatig optical cable; distributed sesig [1-3] 3 TDR [4-5] TDR 1BAK1B5 413636973 11CB7165 1391 *
5. C-DTS 911 Dalto 1984 [6] 3 a [7] [8] 3 ROTDR DTS [9-11] [1] TDR C-DTS C-DTS C-DTS C-DTS C-DTS [ t 1 t ][ t 1 t ] T t T t i1 ( Ti ) (1) T t T i [ t 1 t ] T t w T t w U Q1 I R () R Q 1 U R I R I Q 1 [13] T Q (3) u Q T u Q3 Q1 Q ( T T), (4) Q 3 c m T T 4 T I R( T T) (5) 5 I R T T (6) T T T u u u T 6 u ktb (7) k b T u I R T T T u u k b
91 14 w s (8) w s w w w aw (9) a w 79 k s b w T (1) a a a wkt 1 b1 (11) k s b k1 b1 k 1 b 1 a a a 11 111 ( T ) i i1 w k b (1) wktt b (13) k b 13 T t w k b C-DTS DTS ROTDR ROTDR [14-15] 4 I v RT ( ) e IS vs hcv F F KT (14) R(T)I F IS v F v S c v h K T ct X (15) 1415 C-DTS C-DTS NZS-DTS-C11 1 NZS-DTS-C11 Fig. 1 Diagram of NZS-DTS-C11 C-DTS C-DTS 4 DTS T T T t Tt w w
5. C-DTS 913 7.33 V/m 18 mi PVC C-DTS Fig. Workig process of C-DTS system C-DTS w T t wktt b k b T t 3 C-DTS PVC Fig. 3 Basic cofiguratio of tests DTS DTS NZS-DTS-M6 1 m.1 6 km 3 mm 19.4 Ω/m 5 PVC.7 m 33.63 m 4 PVC PVC DTS Fig. 4 Istallatio process of test device [13] d 1.13 mm d 6.9 mm 1.1 g/ 3 w sat.9%.3.9% 5%1%15%% C-DTS T T t 4 33.63 m DTS 1 m 33 33 5 5 3 mi 3 mi
914 14 Fig. 5 Time-history curves of heatig of measurig tube uder differet moisture cotets T t w [ t 1 t ] t 1 t t 363931315318 mi 6 Fig. 6 Relatioship betwee T t ad w of soils at differet time..itervals 6 6 T t w w3 6 mi.514tt 3.83 w3 9 mi.553tt 33.13 w3 1 mi.5648tt 33.5 (16) w3 15 mi.6819tt 38.48 w3 18 mi.74tt 39.67 16 C-DTS C-DTS C-DTS 13 C-DTS C-DTS C-DTS 8% 363931315 318 mi 16 1 Table 1 Compariso of moisture cotets calculated by T t at differet time itervals /mi /% /mi /% 36 6 11.3 3.3 39 9 1.9.9 31 1 9.68 1.68 315 15 8.96.96 318 18 8.13.13 1 6 318 mi 18 mi 3 mi 5% C-DTS [5%w sat ]
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