PSI - Issue 20

Oleg Naumov et al. / Procedia Structural Integrity 20 (2019) 53–56 Oleg Naumov et al. / Structural Integrity Procedia 00 (2019) 000 – 00

54

Fig.1. Changes in the pipeline position effected by the following: (a) heave, (b) thermokarst, (c) sag.

2. Setting and Method of Solution The paper presents the calculation of 520 mm outer diameter (355 JR steel - 17G1S (Russian: 17Г1С) analogue), 30 m length oil pipeline of underground routing (1.5 m depth of burial) in the permafrost soil conditions, which runs 25 ⁰ C temperature oil under 5 MPa pressure, with 0 ⁰ C temperature pipe casing. The simulation was performed by means of software package SolidWorks Simulation. As the pattern of calculation, the section of the oil pipeline fixed in (0 and 30 m) boundary regions was selected with the parameters compliant with the stresses effected by the thermokarst, heave and sag. The static analysis was performed using the Finite Element Method. 3. Calculations and Results The calculation results are presented in Fig. 2 – 5 and Table 1.

Table 1. Maximum stresses and travels of the oil pipeline section.

Type of stress

SSS in the pinch point zone (start of the section), MPa

SSS in the maximum travel zone, MPa

SSS in the pinch point zone (end of the section), MPa

Maximum travel, mm

Heave

260.2 98.4

229.2 54.4

250 96.3 369 383

15.1 – 17.6 7.5 – 8.2 163.7 - 178.6 153.3 - 160

Thermokarst

Cave

401 395

310 285

Heave and sag

Fig. 2. SSS under the soil heaving.

Fig. 3. Thermokarst zone SSS.