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Ground vibration induced by rock blasting is one of the most crucial problems in surface mines and tunneling projects. Hence, accurate prediction of ground vibration is an important prerequisite in the minimization of its environmental impacts. This study proposes hybrid intelligent models to predict ground vibration using adaptive neuro-fuzzy inference system (ANFIS) optimized by particle swarm optimization (PSO) and genetic algorithms (GAs). To build prediction models using ANFIS, ANFIS–GA, and ANFIS–PSO, a database was established, consisting of 86 data samples gathered from two quarries in Iran. The input parameters of the proposed models were the burden, spacing, stemming, powder factor, maximum charge per delay (MCD), and distance from the blast points, while peak particle velocity (PPV) was considered as the output parameter. Based on the sensitivity analysis results, MCD was found as the most effective parameter of PPV. To check the applicability and efficiency of the proposed models, several traditional performance indices such as determination coefficient (R2) and root-mean-square error (RMSE) were computed. The obtained results showed that the proposed ANFIS–GA and ANFIS–PSO models were capable of statistically predicting ground vibration with excellent levels of accuracy. Compared to the ANFIS, the ANFIS–GA model showed an approximately 61% decrease in RMSE and 10% increase in R2. Also, the ANFIS–PSO model showed an approximately 53% decrease in RMSE and 9% increase in R2 compared to ANFIS. In other words, the ANFIS performance was optimized with the use of GA and PSO.
相似文献A new remediation technique is proposed to mitigate large deformations imposed on buried pipeline systems subject to permanent ground deformation. With this technique, low-density gravel (LDG) with high porosity, such as pumice, is used as backfill in the trench containing the pipe near an area susceptible to PGD. This countermeasure decreases soil resistance, soil-pipe interaction forces and strain on the pipe as the pipeline deformation mechanism changes to a more desirable shape. Expanded polystyrene geofoam has been introduced to decrease the density of the pipeline backfill; however, LDG is more efficient regarding workability during construction, environmental effects, durability, fire safety, and cost-effectiveness. A series of centrifuge model experiments in which the pipelines were subjected to reverse faulting was conducted to evaluate the proposed method. During faulting, the axial and bending strain and pipe deflection were measured. A comparison of the responses of the remediated pipeline and the pipeline without remediation indicates that the proposed technique substantially mitigates the effects of large deformation.
相似文献Tunneling is often unpopular with local residents and environmentalists, and can cause aquifer damage. Tunnel sealing is sometimes used to avoid groundwater leakage into the tunnel, thereby mitigating the damage. Due to the high cost of sealing operations, a detailed hydrogeological investigation should be conducted as part of the tunneling project to determine the impact of sealing, and groundwater modeling is an accurate method that can aid decision-making. Groundwater-level drawdown induced by the construction of the Headrace water-conveyance tunnel in Sri Lanka dried up 456 wells. Due to resulting socio-environmental problems, tunnel sealing was decided as a remedy solution. However, due to the expectation of significant delays and high costs of sealing, and because the water pressure in the tunnel may prevent groundwater seepage into the tunnel during operation, there was another (counter) decision that the tunnel could remain unsealed. This paper describes groundwater modeling carried out using MODFLOW to determine which option—sealed or unsealed tunnel—is more effective in groundwater level recovery. The Horizontal Flow Barrier and River packages of MODFLOW were used to simulate sealed and unsealed tunnels, respectively. The simulation results showed that only through tunnel sealing can the groundwater level be raised to preexisting levels after 18 years throughout the study area. If the tunnel remains unsealed, about 1 million m3/year of water conveyed by the tunnel will seep into the aquifer, reducing the operational capacity of the tunnel as a transport scheme. In conclusion, partial tunnel sealing in high-impact sections is recommended.
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