Inserted hose lining (IHL) is a trenchless technology with high application potential in repairing urban gas pipelines. Since the application of this technology in gas pipelines is still in the ...developing stage, it is necessary to study its feasibility. Based on the mechanical properties of the composite lining material used in this technology, the stress analysis is carried out using ANSYS Workbench software. In this paper, two kinds of aging pipelines with defects are considered, and the repair effect of IHL technology is studied. One is the pipeline with uniform corrosion defect, and the other is the pipeline with corrosion perforation defect. For the pipeline with uniform corrosion defect, the influences of residual thickness, diameter, pressure, and buried depth on pipeline stress are studied. For the pipeline with corrosion perforation defect, the influences of the corrosion perforation position, the corrosion perforation size, diameter, and pressure on pipeline stress are studied. According to the allowable stress of the steel pipeline, the applicable scope of the lining under different conditions is obtained. Based on the analysis results, the main conclusions are as follows: (1) IHL method can effectively reduce the stress of the old pipeline, and the old pipeline is the primary pressure bearing component. (2) Under uniform corrosion conditions, the residual thickness is inversely related to the pipe stress, the pressure and diameter are positively correlated with the pipe stress. (3) Under the condition of corrosion perforation, it is the most dangerous situation that the corrosion hole is near the pipe bottom.
AbstractThis study examines the feasibility and effectiveness of the sprayed-in-place pipe (SIPP) technology for concrete pipe repair, with a focus on a dual-component, high-strength spray lining ...material enhanced with an epoxy resin sealing layer. The research was conducted using a simulated experiment rig, tailored to specific environmental characteristics and the specifications of BONNA pipe, a type of precast reinforced concrete pressure pipe. This setup allowed for a detailed feasibility study of an automated spray process under simulated working conditions. The experimental process involved applying the lining material to concrete substrates, achieving a smooth, pinhole-free surface, with quality control managed using a high-voltage spark tester. The lining demonstrated exceptional impermeability, showing no penetration under 3 MPa water pressure, and maintained strong adhesive strength with the substrate, exceeding 6 MPa as indicated by substrate concrete failure during testing. Furthermore, the technique’s applicability in complex scenarios was tested, including automatic spraying inside 90° elbows, with lining thickness variations staying within acceptable limits. These findings suggest that the process is highly suitable for on-site pipeline conditions, offering a robust and reliable solution for enhancing the durability and integrity of pipeline infrastructures. This study provides practical engineering references for the SIPP repair method, demonstrating its potential as a significant advancement in pipeline repair and maintenance.
•The mechanical behavior of pipes installed by HDD under seismic load is analyzed.•The mechanical behavior of pipes installed by HDD and open-cut methods is compared.•The effects of transverse and ...axial seismic load are revealed.
The present study investigates the mechanical behavior of high-pressure pipelines installed through horizontal directional drilling (HDD), a crucial trenchless installation method, under seismic loads. Utilizing the finite element method and artificial viscoelastic boundary conditions, this paper analyzes the stress response of pipelines subjected to seismic loads in two directions. The seismic loads are applied using the response spectrum method, and the pipeline stress is analyzed in time history. A comparison of the stress in pipelines installed through the HDD method and the traditional open-cut method is conducted, and the impact of earthquake magnitude on pipeline stress is evaluated. The results indicate that the pipeline stress is greater when the seismic acceleration acts transversely, with bending deformation being the dominant mode of response. A 9.29% increase in maximum stress is observed for each increment in earthquake magnitude. Furthermore, the stress in pipelines installed through the HDD method is 48% lower than that of pipelines installed using the open-cut method when subjected to transverse seismic loads.
Novel saponins possessing fertility-regulating activity, hainaneosides A (1) and B (2), have been isolated from the twigs and stems of Marsdenia hainanensis, and their structures have been elucidated ...unambiguously as 12-nicotinoyl sarcostin-3-O-β-d-glucopyranosyl-(1→4)-3-O-methyl-6-deoxy-β-d-allopyranosyl-(1→4)-β-d-oleandropyranosyl-(1→4)-β-d-cymaropyranosyl-(1→4)-β-d-cymaropyranoside and 12-nicotinoyl-20-cinnamoyl sarcostin-3-O-β-d-glucopyranosyl-(1→4)-3-O-methyl-6-deoxy-β-d-allopyranosyl-(1→4)-β-d-oleandropyranosyl-(1→4)-β-d-cymaropyranoside using NMR spectroscopic techniques and chemical transformations.
