Approach for evaluating instantaneous impact forces during submarine slide-pipeline interaction considering the inertial action

Several engineering practices have shown that the excavation of shallow-buried tunnels beneath major roads, as well as the selection of appropriate engineering measures and construction methods, has a significant impact on road surface settlement. Therefore, field monitoring and numerical simulation are adopted in this study to analyze the effect of the cross diaphragm (CRD) excavation method on surface settlement for the under-construction Yüan 1 railroad tunnel. The findings show that during the excavation of the four divisions of the CRD excavation method for shallow-buried tunnels, the amount of surface settlement caused by the excavation of part 1 accounts for 40% of the total surface settlement, followed by the excavation of part 3, accounting for 30% of the total surface settlement, and the difference between the excavation of parts 2 and 4 is insignificant, with part 2 slightly larger than part 4. The main influence of the CRD method on surface settlement for shallow-buried tunnels is 0.64–0.86 times the cavity diameter from the tunnel median, within which the final surface settlement caused by excavation is within the same horizontal range, and beyond which the surface settlement is prone to dramatically decline. By applying advanced grouting and adjusting the construction method of CRD based on the monitoring data, the effect of the CRD excavation method on surface settlement can be controlled.

Section: Discussionmentioning

confidence: 99%

The effect of CRD method and auxiliary construction on surface settlement in shallow-buried tunnels

Zhang¹,

Pan²,

Chen³

et al. 2023

“…The coefficient of lateral earth pressure is one of the key parameters of the Terzaghi loose earth pressure theory. However, a consensus has still not been reached in the calculation of the coefficient of lateral earth pressure K, with the primary point of controversy being the selection of the principal arch stress to be used in the calculation (Handy, 1985;Wan et al, 2019;Fan et al, 2022). Xu et al (2018) and Dong et al (2022) discovered that a convex principal stress arch is more aligned with actual circumstances and the principal stress arch traces adopt a circular arc form.…”

Section: Investigating the Coefficient Of Lateral Earth Pressure For ...mentioning

confidence: 99%

A method of calculating water and soil loading on top of shallow shield tunnels near water areas

Zhu

Chang²,

Cui³

et al. 2023

Long-term water seepage in shield tunnels has a serious impact on water and soil loading on the outer surfaces of a shield segment near water areas. A theoretical analysis was used to obtain a formula to express the average vertical seepage gradient at the top of the tunnel. A formula for calculating the coefficient of lateral earth pressure for the principal stress arch effect was utilized. A model that takes into consideration the effects of long-term water seepage on the shield tunnel’s water and soil load was designed. Based on this calculation model, the variation law of the water and soil loading on top of shield tunnel near water area with the internal friction angle in the soil body, the density of the soil, the tunnel depth-to-diameter ratio, the water head of the external section, and the amount of water seepage per unit length is studied. Based on the geological conditions and field survey results of water and soil loading of two typical segments of the Maliuzhou Waterway section of the Hengqin Tunnel, a comparative analysis of the theoretical results and field survey measurements was performed for different calculated conditions. The research shows that the proposed model is able to perform a reasonably effective evaluation of the water and soil pressure at the top of the shield tunnel for the marine and land segments of the shield tunnel; and, when compared with Dimitrios Kolymbas’ effective stress method and Terzaghi’s Principle, the method shown in this paper has fewer errors. The results of the associated research are sufficient to reasonably design and propose a theoretical basis for underwater shield tunnels.

“…The results revealed that the density of backfill soil around the buried pipes and the installation process have significant effects on the mechanical properties and deformation characteristics of the pipelines. In recent years, with the development of the numerical simulation technique, more and more factors were considered to study the stress characteristics of buried pipelines (Meesawasd et al, 2016;Zhang et al, 2016;Abbas, 2017;Pires and Palmeira, 2017;Zhang and Xie, 2019;Pan et al, 2021;Bai et al, 2021;Wang et al, 2022;Fan et al, 2022;Dong et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Model tests of the raw-water pipeline under the excessive stacking load

Wang

Wang²,

Chen³

et al. 2023

To investigate the effect of excessive stacking loadings on the deformation of raw-water pipelines, a model test was designed based on the analogous theory in this paper. The design of the model box, selection of pipeline material, and preparation of remolded soil were conducted, respectively. A theoretical formula was derived to convert the results of the model test into actual ones. Then, the field test data and three-dimensional numerical values were employed to verify the correctness of the model test results. Finally, the stresses of pipelines were discussed under different loading conditions, pipe diameters, buried depths, and compactness of underlying soils, and the guidelines for pipeline protection were proposed based on the results of the model tests. It can lay a solid theoretical and practical foundation for the protection of buried pipelines.