The Long-Term Mitigating Effect of Horizontal Ground-Source Heat Exchangers on Permafrost Thaw Settlement

This study investigated the long-term effect of horizontal Ground-Source Heat Exchangers (GSHEs) on mitigating permafrost thaw settlement. In the conceptual system, a fan coil was used to chill the recirculating fluid in the linear High-Density Polyethylene (HDPE) ground loop system. A fully coupled thermo-hydro-mechanical finite element framework was employed to analyze multiphysics processes involved in the thaw settlement phenomenon. To investigate the sustainability of the system, a period of 50 years was simulated. Two operational modes were defined: one without and the other with HDPE. Different heat carrier velocities and inlet temperatures, and heat exchanger depths were examined to explore their effects on the thaw settlement rate. It was concluded that the proposed system can effectively alleviate the predicted permafrost thaw settlement over the study period. Moreover, the heat carrier temperature was found to have a prominent impact on the thaw settlement rate amongst other parameters.

Model Tests on Use of Tyre Chips and Fly Ash Chips as a Replacement of Aggregate in Stone Columns

In order to reduce the generated waste in industry the concept of reusability is adopted as an application in the civil engineering field. In this study, the experiments were performed by using shredded tyre chips, chips of fly ash bricks in partial replacement with aggregates passing through 12.5 mm sieve and retaining on 10 mm sieve (IS-Indian standard). The experiments with partial replacement of stone columns were carried out at various proportions of tyre chips and fly ash brick chips in soft clay. Corresponding settlement rate was noted by loading the stone column gradually through a hydraulic jack for various L/D ratios. On comparison the final results it was concluded that the stone column with replacement of 75% tyre chips and 25% coarse aggregate proved good to carry maximum load and with lower settlement rate than ordinary stone column without replacement.

Understanding the Influence of Building Loads on Surface Settlement: A Case Study in the Central Business District of Beijing Combining Multi-Source Data

In metropolitan areas, the static load of high-rise buildings may result in uneven settlement, which seriously threatens residents’ living safety. Studying the response relationship between the additional stress of high-rise buildings and foundation settlement plays an important role in ensuring the safe development of metropolitan cities. Firstly, based on Persistent Scatterers Interferometric Aperture Radar (PS-InSAR) technology, we used 68 descending TerraSAR-X images to obtain the surface settlement in the study area from April 2010 to October 2018, which were validated with leveling benchmark monitoring results. Secondly, we calculated the additional stress of the building loads to quantify its effect on the uneven settlement in the Central Business District (CBD) of Beijing. Finally, two sets of characteristic points were selected to analyze the response relationships between foundation settlement and additional stress generated by building loads. The findings show: (1) The surface settlement rate varied from −145.2 to 24 mm/year in the Beijing Plain. The InSAR results agree well with the monitoring results derived from the leveling benchmark; the Pearson correlation coefficients were 0.98 and 0.95 in 2011–2013 and 2015–2016, respectively. (2) The stress results show that the depth of the influence of the static load of high-rise buildings was 74.9 m underground in the CBD. (3) The spatial distribution pattern of the additional stress is consistent with the foundation settlement. A characteristic point with greater additional stress in the same group has a higher foundation settlement rate. This relationship has also been found between the uneven foundation settlement and additional stress gradients. These findings provide scientific support for mitigating economic losses due to foundation settlement caused by additional stresses derived from building loads.

Litigation Spending and Care under the English and American Rules: Experimental Evidence

We investigate the effects of fee-shifting in an experimental litigation game. In our setup, a defendant may cause harm to a plaintiff. The defendant can take precautions to lower the probability of harm at a personal cost. In case of harm, the parties go to court, where the winner is determined by a rent-seeking contest. We compare two fee-shifting rules: under the American rule each party bears its own litigation costs; under the English rule the loser has to reimburse the winner’s expenses. We test the hypothesis that the English rule leads to higher litigation spending but also to higher care compared to the American rule. The experimental results largely support the predictions: fee-shifting leads to higher litigation spending, which motivates higher levels of care. When the parties are offered the possibility to settle their dispute out of court, fee-shifting leads to even higher litigation spending in court, but it neither affects the settlement rate nor care.

Sedimentation of Irregular Shaped Microplastics Under Steady and Dynamic Flow Conditions

Because of different compositions, physicochemical properties and shapes in nature of the microplastics (MPs), their migration process in the environment is very different, which makes it difficult to predict the behavior trajectory. This article mainly studies the sedimentation law of MPs under static and dynamic water conditions. Four kinds of materials, respectively polystyrene (PS), Polyamide (PA), polyethylene terephthalate (PET) and polyvinyl chloride (PVC), about 1230 MP particles with irregular shapes are selected for sedimentation experiments. They are divided into three shapes: near-sphere, polygonal ellipsoid and fragment. The experimental results show that the near-sphere MPs settled at the fastest rate, followed by the polygonal ellipsoid MPs, and the fragmented MPs settled at the slowest rate. By the force analysis of MPs in the settlement process, and the theoretical formula of MP settlement rate with their shape, particle size, density and water density are obtained, which has better fitting degree.

PS-InSAR based surface subsidence analysis in Changchun metropolitan area

The monitoring of urban land surface subsidence is the main task of urban disaster prevention and mitigation. In this paper, the land surface subsidence process in Changchun metropolitan area is calculated based on PS-InSAR technology by using the SLC data of Sentinel-1B with 50 scenes within the metropolitan area of Changchun from 2016 to 2020. The results show that the metropolitan surface of Changchun is basically in a stable state, the main settlement is located in the southeast of the metropolitan around the Century Square, the maximum settlement rate is 20.45mm/a, the average settlement rate is 2.98mm/a, the correlation coefficient between the settlement results calculated by PS-InSAR and the second-class leveling verification results reaches 0.67, which indicates that the regional settlement results calculated by PS-InSAR have high reliability. The subsidence area is dominated by the geological structure of the Mesozoic Cretaceous Yaojia Formation, with many intercalations of fine silty sand rocks and locally containing medium-coarse gravel sandstone. The overall structural stability is poor, which may be the main reason for subsidence in this area.

Seismic Fragility Analysis of High Earth-Rockfill Dams considering the Number of Ground Motion Records

This study analyzes the impact of the number of ground motions on the seismic fragility of a high earth-rockfill dam and the estimation of reasonable fragility parameters based on a sufficient number of earthquake records. In this paper, the vertical deformation is obtained using the three-dimensional finite element program DYNE3WAC combined with the Pastor–Zienkiewicz–Chan model and Biot dynamic consolidation theory. The relative seismic settlement rate is considered the damage index for the seismic fragility analysis of the dam. The fragility curves of the high earth-rockfill dam are determined by the multiple stripe analysis (MSA) method. A set of seismic waves is chosen based on the spectrum in the Chinese hydraulic structure seismic code. With an increasing number of earthquake records, the coefficients of variation (COV) of the mean and standard deviation (STD) of the relative seismic settlement rate decrease and tend to stabilize when the number of earthquake records reaches 34. The estimated fragility parameters θ and β are constant when the number of earthquake records exceeds 34. The requisite number of earthquake records for an accurate fragility estimation is determined by analyzing the lower and upper confidence intervals for the estimated θ and β. The 95% and 90% confidence interval can accurately estimate the fragility of a high earth-rockfill dam when the number of ground motion records reaches 36 and 32, respectively. The results of the fragility analysis demonstrate that the DYNE3WAC program and MSA method can provide an effective basis for determining fragility curves. Furthermore, the sensitivity analysis of earthquake records is essential for assessing the seismic fragility of high earth-rockfill dams.

Taking a Financial Position in Your Opponent in Litigation

Before filing suit, a plaintiff can take a financial position in a defendant firm. A short position benefits the plaintiff by transforming a negative expected-value claim into a positive expected-value one and by enhancing the claim's settlement value. If the capital market is less than strong-form efficient, the plaintiff also benefits directly from the decline in the defendant's stock price. When the defendant is privately informed about the case's merits, bargaining failures can arise. While aggressive short-selling benefits the plaintiff at the expense of the defendant, moderate levels of short-selling can benefit the defendant and raise the settlement rate. (JEL D82, G14, K41)