# A Case Study of Floating Offshore Super-Long Steel Pipeline Combing with Field Monitoring
## 4 Analysis of Monitoring Results
### Dynamic Regulation  
By real-time monitoring and timely warning and feedback to the construction institution, the construction institution can dynamically adjust the construction operation according to the monitoring feedback situation, avoid the pipeline damage caused by the  
Figure 9: Pipeline Section 2 floating strain.  
deformation of steel pipeline and 3 PE composite material, and ensure the safety of pipeline floating transportation.  
At the beginning of floating transportation of pipeline Section 1, the wind speed was 3 m/s, the flow velocity was 0.35 m/s, and the wave height was 0.15 m, the axis of the pipeline was along the direction of water flow. The strain of the pipeline obtained by on-site monitoring is small and the change amplitude tends to be gentle. When floating at 72 min, a level 6 gale suddenly appears at sea, the wind speed was 6.5 m/s, the flow velocity was 0.55 m/s, and the wave height was 0.45 m. At this time, the angle between the pipeline axis and the flow direction was about 90\({}^{\circ}\). The strain of the pipeline increases and the construction institution notifies the tugboats to increase the towing capacity. However, it is found that the strain suddenly increases and quickly approaches the warning value through monitoring. The monitoring personnel immediately reports the situation to the construction institution. Considering that the situation is caused by too much tugboat thrust, the operator at the construction site should be informed to reduce the tugboats thrust slowly, and always pay attention to the monitoring data, the strain data to be monitored returns to the normal level, that is, stop reducing the thrust of the tugboats. As shown in Figure 10, real-time monitoring and construction cooperate to dynamically adjust the construction operation (Section 2 at the bend is the maximum main strain).  
Figure 10: Dynamic floating construction of pipeline Section 1.  
When the floating movement of pipeline Section 2 begins, the wind speed was 3 m/s, the flow velocity was 0.35 m/s, and the wave height was 0.15 m, the axis of the pipeline was along the direction of water flow. At 48 min of floating transportation, a strong wind suddenly appeared at sea, which was opposite to the floating transportation direction of the pipeline section. The wind speed was up to 6.5 m/s, the wave was up to 0.45 m, and the flow velocity was 0.55 m/s. At this time, the angle between the pipeline axis and the flow direction was about 90\({}^{\circ}\). Dynamic construction is shown in Figure 11. Through monitoring, it is found that the strain at the water surface measurement point on the back of the pipeline continues to increase when it reaches 200 \(\mu\varepsilon\), which is mainly caused by the increase in wind speed and flow velocity. The monitoring personnel immediately gave warning to the construction institution and reports the position of the maximum strain, informing the construction site operators to send an additional tugboat near Section 6 near the midpoint of the inclined pipeline section and continuously adjusting the position of the additional tugboat according to the monitoring data. Although the maximum strain of measuring point 5-2 at 55 min was 337.8 \(\mu\varepsilon\), exceeding the alarm value, it was still within the safety range. After the additional tugboat starts to work, the overall strain of the pipeline gradually reduced and then becomes stable. Finally, the pipeline Section 2 was transported to the designated position safely.  
Figure 11: Dynamic floating construction of pipeline Section 2.