Applied Mechanics and Materials Vols. 170-173

Abstract: This paper presents a method for simulation of water distribution systems with breaks, in which, the leakage and low supply pressure can be considered. The effects of break location and extent on pressure variation of monitoring stations are simulated by numerical examples. It is shown that, the method can be used for estimating the effected area due to breaks; the high sensitivity may be achieved if monitoring stations are uniformly distributed; pressure variations are linear for small breaks and nonlinear for large ones.

Abstract: It is difficult to determine a proper neurons number of the mid-layer when using the BP neural network for water demand forecasting. Aiming at the problem, the BP neural network is presented in this paper for water demand forecasting. A suitable neurons number in the mid-layer is calculated based on the empirical formula method and trial and error method. A certain basin in China is taken as a case study. The results indicate that the mean relative error is 2.42%. The water consumption is 42.8 billion m3 in 2015 and 43.6 billion m3 in 2030 in the study area. The results are useful for water resources planning and management.

Abstract: It is the necessity of the modern city development to implement the informatization management of water supply pipe network. The paper introduces the design of a data acquisition and monitoring system for water supply pipe network based on GPRS. It presents the implement of the hardware and software design of the data acquisition and monitoring terminal which is based on the embedded technology and uC/OS-II operating system, as well as the software design of the monitor center. The communication protocol based on GPRS and Winsock network programming technology is provided. The various field data collected by the terminal are encapsulated and sent to the GPRS module by microprocessor serial port. Then, the GPRS module sends the data to the remote monitor center which realizes the functions such as data process, data storage and statistical analysis. The system works well in the laboratory environment.

Abstract: In this study, microfiltration (MF) combined with oxidation and coagulation was investigated for production of drinking water by Huangpu River. The experiment focused on the effects of various oxidants on reduction in fouling and improvement in quality of treated water. 0.5mg/L of ozone, 1.5mg/L of sodium hypochlorite and 0.3mg/L of potassium permanganate were added before membrane to reduce the fouling. The results showed that significant differences in permeate water and trends of TMP exhibited by adding different oxidants. With ozone as pre-oxidation, permeate water could meet China Drinking Water Regulations (CDWR), however, part of water quality met CDWR with sodium hypochlorite and potassium permanganate as pre-oxidation. TMP increased slowly during filtration period for a long time when ozone and sodium hypochlorite were added. With potassium permanganate as pre-oxidation, rapid increase in TMP was observed, which can be attributed to a lot of manganese oxides deposited in the membrane by analyzing chemical cleaning water. Chemical cleaning of membrane could decrease TMP to initial level. Analysis of chemical cleaning solution indicated that organic matters was responsible for the most fouling, and ozone could reduce membrane fouling effectively.

Abstract: On account of micro-polluted raw water, high rate up-flow biological aerated filter (HUBAF) is used to remove the ammonia nitrogen and micro organic pollutants in raw water. Using ceramisite as filtration media, at a diameter of 6mm to 10 mm, a surface density of above 1g/cm³ and a filtration rate of 16 m/h to 20 m/h, ceramisite layer is in a state of micro expansion, which is beneficial to keep a high nitrification efficiency. On account of raw water where NH₃-N is below 4mg/L, NH₃-N concentration t can be stabilized at less than 0.5 mg/L in HUBAF effluent. Since lack time of biochemical action, the COD_Mn removal rate by HUBAF is low. As the effluent of BAF carried abundant amounts of microbes and dissolved oxygen, it increased the COD_Mn removal rate by 11% in final effluent compared to the individual conventional process of “flocculation-sedimentation-filtration-disinfection”. The turbidity removal efficiency is only the 1/3 of ordinary BAF, which reduces the head loss and energy consumption, and multiple filters to share a centralized aeration system is possible. In addition, HUBAF system is aerated by the single-pore aeration filter heads under the filtration board, equipped with both up-flow and down-flow backwash systems and no need for extra grit chamber, HUBAF is convenient for maintaining and administration.

Abstract: On large-scale pipelines at a water supply capacity of 5-10 m³/s, the bursted flow can reach hundreds to thousands of cubic meters within a few minutes, which could trigger secondary disasters in the densely populated areas. But the accident is hard to be monitored and found, because the leakage flow is often only 1% to 5% of the water supply capacity. This paper presents the simultaneous manometry for the burst and leakage monitoring along the pipelines. The research found that it can alarm timely in 3min to 5min and provide key information such as detonation location and the amount of the explosion leakage. The method has been applied to Xijiang River Diversion Project in China and the water supply capacity is 3.5 million m³/d(40.5m³/s).

Abstract: A model for simulating combined drainage networks in Chuangfang river basin of Kunming City based on the Storm Water Management Model was established. The type and period of using water base on residential area, marketplace, school area, and guesthouse area Kunming city were introduced into the model, and their infection for drainage system was research. The results show that simulation results of two outlets flow have coherence with monitoring data based two typical rainfall in Kunming, the Nash-Sutcliffe efficiency coefficient is 0.71-0.82. And the model can be using analyze ‘bottleneck’ nodes and restricting conduits, simulating the running status of drainage network of combined drainage at raining and draining peak time of sewage water. The research provide strong technical support for rebuild drainage network in Kunming or other city.

Abstract: In order to investigate the leakage amount in the water supply networks in the countryside regions, a new method combined with GIS and DEM to estimate the leakage amount at water supply network nodes has been put forward. It is proposed according to the Chinese node leakage model, and it takes advantage of the strong spatial annalistic function of the GIS. The emphasis is put on the study of the topology relationship of the water supply networks which are built based on the GIS network analysis. And DEM model is used to calculate the elevation at the network nodes. And then the leakage amount of the water supply network nodes is estimated. Finally, specific examples have been verified in order to illustrate that the GIS-based method to estimate leakage amount at the water supply network nodes is efficient.

Abstract: In coastal areas, soft soil treatment is the challenge which must be faced in process of engineering construction. Among numerous treatment methods, dynamic drainage consolidation method is a new and effective method. In this paper, The Finn constitutive law reflecting dynamic pore pressure has been applied to dynamic drainage consolidation analysis. The results show pore water pressure behaves a pulse response proces for the impact, vertical drainage systerm increase the effective drainage channels, speed up the drainage process.

Abstract: This paper introduces the application of dynamic drainage consolidation method in subgrade strengthening. Treatment result shows that the standard values of foundation bearing capacity are totally more than 120kPa，settlement of post –construction is less than 150 mm and differential settlement is less than 100mm，and the reinforced Depth of subgrade is about 9 m.