To enhance the safety and reliability of urban buried water supply networks, this study developed a monitoring and early warning system based on wireless transmission networks and Internet of Things (IoT) technology. Through numerical simulations, the structural tilt warning thresholds for ductile iron pipes were determined. Additionally, in conjunction with meteorological data, monitoring pore water pressure serves as a supplementary indicator for detecting potential pipeline leakage. This study further analyzed pipeline strength warning thresholds based on strength theory. In practical engineering applications, the proposed system enables real-time monitoring of the operational status, service environment, and structural integrity of buried water supply networks. Data analysis revealed the influence mechanisms of backfill soil conditions, daily operations, and third-party construction activities on the structural behavior and stress state of water supply pipelines. Results indicate that during the initial backfilling phase, uneven backfilling and soil settlement induce significant variations in pipeline tilt angle and stress distribution. Furthermore, longitudinal stress in the pipeline exhibits a strong correlation with ambient temperature fluctuations, with a pronounced increase observed during colder months. Notably, third-party construction activities were identified as a major contributor to pipeline anomalies, with all recorded early warnings in this study being attributed to such external interferences.

To investigate the influence of the filling thickness and internal water pressure on the stability of a water supply pipeline, a typical pipeline of the Sun Mountain Water Supply Project is selected as the research object. A numerical simulation method is adopted to establish a three-dimensional finite element model integrating a double-line pipeline-artificial fill-foundation to study the influence of different single-layer filling thicknesses and internal water pressures on the mechanical properties of the double-line pipeline. The results of the study show that the relative error between the intrinsic mode of the finite element model of the double-line pipeline and the frequency identified by the dispersion entropy variational mode decomposition (DVMD) method on the measured vibration signals is only 1.55%, which confirms the validity of the finite element model and the accuracy of the results. With increasing soil filling and increasing single-layer filling thickness, the vertical displacement of the double-line pipe gradually increases, with a maximum value of 12.24 mm. With increasing single-layer filling thickness, the rate of increase in the vertical displacement of the double-line pipe increases. With increasing soil filling, the tensile and compressive stresses on the double-line pipe increase gradually, with maximum values of 0.148 MPa and 0.568 MPa, respectively. When the number of cycles is the same, the tensile and compressive stresses of the pipe sheet increase with increasing single-layer filling thickness. When the internal water pressure is 0.6 MPa, the trends of the inner and outer circumferential deformation and tensile and compressive stresses of the left and right lines of the pipes are basically the same. The outer stresses are lower than the inner stresses, among which the tensile stresses are reduced by 25% and 20.1%, and the compressive stresses are reduced by 16% and 18.2%, respectively. Under the joint action of the earth pressure and internal water pressure, the deformation of the double-line pipeline and the compressive stress tended to decrease and then increase, and the tensile stress gradually increased. The research results provide a theoretical reference and basis for similar water supply pipeline projects.

Although Novel Polymeric Alloy (NPA) geocells have been applied to stabilize road bases against the freeze-thaw (F-T) damage in practice, the relevant research lags the application. A scarcity of research has been reported to comprehensively evaluate the benefits of geocell stabilization in enhancing the F-T performance of bases. This study aims to investigate quantitatively the F-T performance of geocell-stabilized bases, focusing on two influencing factors-i.e., water supply and degree of compaction in the bases. A series of model-scale experimental tests (19 tests) was conducted using an upgraded customized apparatus. The results showed that the inclusion of geocells was beneficial for reducing frost heave and thaw settlement as well as mechanical properties (i.e., stiffness and ultimate bearing capacity) of road bases. The benefit of geocells was more remarkable for the well compacted bases than for the poorly compacted bases. The benefit was more pronounced in the open system than in the closed system.

Determining the seismic performance level of shaft structures is crucial due to their vital role in ensuring a water supply. Since these are underground structures, the loads they encounter and the structural modeling processes differ significantly from those of above-ground structures. Accordingly, the primary aim of this paper is to introduce a new modeling methodology for the seismic performance assessment of shaft structures, considering all relevant parameters. This unique approach also incorporates pertinent sections from various applicable local seismic codes. For this purpose, a total of 15 shaft structures located on the historic Atik Valide Waterway, constructed in 1583, were examined. To create numerical models of the shafts, soil exploration parameters were utilized, and the shaft surface-soil interaction was represented by nonlinear p-y springs. An integral part of the presented methodology involved segmenting the shafts at regular intervals, with each segment defined as a separate story. The analysis results demonstrated that the modeling methodology is accurate and aligns well with the observed conditions of the shafts. Considering the significant risk of extensive damage to sewerage systems in urban areas due to soil liquefaction during seismic events, this study is anticipated to serve as a valuable reference in the literature by introducing a new, accurate methodology for identifying potential seismic risks.

Urban water supply networks are crucial for the transportation of water resources. However, with the increasing frequency and severity of cold wave disasters linked to climate change, the impact on water supply systems has become a critical concern. These impacts include pipe failures, customer water outages, and challenges in meeting peak winter water demand. To address this, our study analyzes data from cold waves in Shanghai from late 2020 to early 2021. We statistically examined daily water supply volume, pressure, and pipe failures to detect abnormal changes. We also analyzed pipe failure rates based on different characteristics to identify which pipes are most vulnerable to cold wave damage. Understanding the winter cold wave's effects can help water companies prioritize maintenance on aging pipes before such events, reducing damage and improving service. This research adds to the understanding of climate change's impact on urban infrastructure and provides valuable insights for global water companies to optimize their maintenance strategies.

The corrosion-protection liner (CPL) technology consists of installing flexible plastic liners with anchoring studs inside existing pipelines and subsequently filling cement mortar to the gap between the waterproof liner and the pipeline. With the excellent chemical resistance, impermeability and fast construction speed, CPL provides an economical and environmentally friendly alternative for pipeline rehabilitation without large-scale excavation. However, the seismic performance of water supply pipelines after being retrofitted with CPL has not been well studied yet. In this study, a series of full-scale quasi-static experiments were firstly conducted on ductile-iron push-on joints before and after reinforcement with CPL to investigate the nonlinear behavior of the joints under longitudinal load and transverse bending. Simplified numerical models of straight pipelines with joints before and after retrofitting in the non-uniform site were then developed in the OpenSees platform, and incremental dynamic analysis (IDA) were performed with consideration of nonlinear soil-pipeline interaction. Twenty-eight pairs of ground motions with the peak ground velocities (PGV) collectively scaled from 200 mm/s to 3000 mm/s were used as inputs. Seismic fragility curves of the pipelines before and after retrofitting were developed with respect to the optimum intensity measure, PGV. It can be seen from the experimental results that the longitudinal load and bending moment capacity of the push-on joint increased about 400% and 20% after CPL reinforcement, respectively, and the joint opening and rotation decreased about 20% and 18% after retrofitting. Numerical results show that the CPL reinforced pipelines exhibit better seismic performance and CPL effectively reduces the failure probability of segmented pipelines under earthquake ground excitations.