Ground Surface Deformation Caused by Pipe Jacking Construction in a Soft Soil Area: An Experiment-Based Study

Abstract

Soft soil has the characteristics of high compressibility, large void ratio, and strong structure. Therefore, it is more likely to cause surface subsidence or even surface cracking and collapse when laying oil and gas pipelines in soft soil areas through the pipe jacking method. In this study, test soil was pressurized using a flexible loading bladder, and variable formation losses brought on by pipe jacking were mimicked by varying the loading bladder’s water injection level. The surface deformation brought on by pipe jacking construction is related to the four parameters of stratum loss rate, overburden load, soil disturbance, soil tension fissures, and horizontal deformation. The findings demonstrate that the surface deformation brought on by the excavation gradually reduces and starts to stabilize after the thickness of the overlying soil layer on the pipe jacking surpasses 1.5 times the diameter of the pipe jacking. The constructed settling tank is broader the deeper the jacking pipe is submerged. Further ground surface settling will be exacerbated by the weight above the jacking pipe. The maximum ground surface deformation value will decrease with an increase in the overlying load when the overlying load is high (0.018 MPa).

Transfer-Learning-Based Temperature Uncertainty Reduction Algorithm for Large Scale Oil Tank Ground Settlement Monitoring

“…The main derivation for low-coherence interferometry was copied from Ref. [2], as 𝐼(𝑄) = 𝐼 (1) (𝑄) + 𝐼 (2) (𝑄) + 2√𝐼 (1) (𝑄)√𝐼 (2)…”

“…where 𝛾 12 𝑟 is the real part of the complex degree of coherence 𝛾 12 ; 𝐼 (1) (𝑄) and 𝐼 (2) (𝑄) are the optical intensities from the two interference paths, respectively; and 𝐿 𝐴𝐵 and 𝐿 𝐶𝐷 are the optical paths between mirrors A and B and mirrors C and D, which are represented by red arrows in Figure 2b above. The optical principle is shown in Figure 2b.…”

“…where 𝑨 is the bias matric, and 𝑔 is the sigmoid function, defined as The connections between nodes represent the weights, and these connections between layers form the weight matrices, denoted as W (1) and W (2) , which govern the calculation process between layers. Suppose there is one sample containing three elements: i 1 , i 2 , and i 3 .…”

“…The weight matrix W (2) and bias matric B are modified based on gradient between the output layer and the hidden layer. Subsequently, the weight matrix W (1) and bias matric A are modified based on the gradient between the hidden layer and the input layer. This modification process iterates until the desired level of accuracy is achieved.…”

“…Ground settlement in oil tanks is a critical factor that can compromise their structural integrity and service life [ 1 , 2 , 3 , 4 ], as depicted in Figure 1 a. This emphasizes the importance of prioritizing GS monitoring for large scale infrastructures.…”