Cold Regions Science and Technology最新文献

{"title":"Application of the improved twin-shear unified strength theory to the multiaxial strength of S2 columnar ice","authors":"Zihan Bian ,&nbsp;Xin-Dong Wei ,&nbsp;Yan Huang ,&nbsp;Gao-Feng Zhao","doi":"10.1016/j.coldregions.2025.104574","DOIUrl":"10.1016/j.coldregions.2025.104574","url":null,"abstract":"<div><div>An enhanced twin-shear unified strength theory is presented in this study, effectively decoupling the dual effects of intermediate principal stress on S2 columnar ice. By introducing two novel parameters, <span><math><msub><mi>λ</mi><mn>1</mn></msub></math></span> and <span><math><msub><mi>λ</mi><mn>2</mn></msub></math></span>, the improved model separately quantifies the weakening and strengthening contributions of <span><math><msub><mi>σ</mi><mn>2</mn></msub></math></span> to the multiaxial strength, thereby overcoming limitations in traditional formulations where these effects were coupled. The rate-dependent behavior and anisotropic responses under various loading directions are not only captured by the proposed model, but its descriptive scope of the intermediate principal stress inflection points is also extended from a linear to a surface-based representation. Biaxial and triaxial experimental data are systematically analyzed to validate the model, with results indicating a significant increase in both the strengthening and weakening effects as strain rates rise. Furthermore, the enhanced theory is integrated into a constitutive framework to compute the variable failure envelope of S2 columnar ice, which is subsequently implemented in Four-dimensional Lattice Spring Model (4D-LSM). Numerical simulations demonstrate that the modified envelope surface accurately reproduces experimental observations across diverse strain rate conditions and loading orientations. An orthotropic envelope surface design is also proposed to incorporate anisotropy induced by columnar jointing, thereby lending physical significance to the modification term. Moreover, the refined formulation bridges the gap between theoretical analysis and practical simulation, providing a robust framework for evaluating complex multiaxial stress states in anisotropic ice. Overall, comprehensive insights into the intermediate principal stress effects are provided in this study, and the characterization of S2 columnar ice is significantly improved.</div></div>","PeriodicalId":10522,"journal":{"name":"Cold Regions Science and Technology","volume":"239 ","pages":"Article 104574"},"PeriodicalIF":3.8,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The mechanical properties of gas-enriched sea ice","authors":"Qingkai Wang,&nbsp;Yubo Liu,&nbsp;Peng Lu,&nbsp;Zhijun Li","doi":"10.1016/j.coldregions.2025.104576","DOIUrl":"10.1016/j.coldregions.2025.104576","url":null,"abstract":"<div><div>To investigate the mechanical properties of sea ice in the Arctic, ice blocks were collected using a ship crane and stored in a cold onboard storage unit during an Arctic expedition. During the transfer of ice blocks from the ship to the transport vehicle after docking, significant brine drainage occurred, artificially increasing the gas volume fraction within the ice. This unexpected shift allowed us to explore the mechanical properties of gas-enriched sea ice and the different impacts of gas and brine on sea ice strength. Examination of the ice crystal structure showed a granular ice layer at the top, underlain by a columnar ice layer. Sea ice samples were machined from the ice blocks for mechanical experiments performed in the laboratory. Three-point bending tests were conducted at ice temperatures of −12 to −3 °C, and uniaxial compressive strength tests were conducted at ice temperatures of −8 to −3 °C with a strain rate range of 10⁻⁶–10⁻² s⁻¹. Ice temperature, density, and salinity of each sample were measured to determine porosity. Results showed that both flexural strength and strain modulus of columnar sea ice exhibited statistically significant decreasing trends with increasing porosity. Flexural strength showed a significant correlation with gas volume fraction (<em>R</em>² = 0.25, <em>p</em> &gt; 0.1) but not with brine volume fraction (<em>R</em>² = 0.37, <em>p</em> &lt; 0.1). Conversely, strain modulus correlated significantly with brine volume fraction (<em>R</em>² = 0.58, <em>p</em> &lt; 0.1) but not with gas volume fraction (<em>R</em>² = 0.06, <em>p</em> &lt; 0.1). Uniaxial compressive strength decreased with increasing porosity and displayed a ductile-to-brittle transition, with strength initially increasing and then decreasing with rising strain rate. The transition strain rate ranged between 1.5 × 10⁻⁴ and 4.0 × 10⁻³ s⁻¹ depending on ice crystal structure. Experimental results from gas-enriched sea ice were compared with previously reported data from natural sea ice (brine-dominated). At equivalent porosity levels, gas-enriched ice exhibited higher flexural strength and strain modulus than natural sea ice, indicating that brine has a stronger influence on bending mechanics than gas. However, the uniaxial compressive strength of gas-enriched ice remained comparable to that of natural sea ice.</div></div>","PeriodicalId":10522,"journal":{"name":"Cold Regions Science and Technology","volume":"239 ","pages":"Article 104576"},"PeriodicalIF":3.8,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Data-theory driven prediction approach for the residual axial load carrying capacity of RC columns under salt freeze-thaw cycles","authors":"Yao Wang ,&nbsp;Weiqing Zhu ,&nbsp;Lixin Wei ,&nbsp;Jinqing Jia ,&nbsp;Yafei Zhang ,&nbsp;Lihua Zhang","doi":"10.1016/j.coldregions.2025.104572","DOIUrl":"10.1016/j.coldregions.2025.104572","url":null,"abstract":"<div><div>This study aims to develop a data-theory driven approach to predict the residual axial load carrying capacity of reinforced concrete (RC) columns of bridges subjected to salt freeze-thaw cycles (SFTCs). The proposed approach integrates a data driven calculation model and a theory driven simulation model to simulate SFTCs, damage inheritance, and the residual axial load carrying capacity. The calculation model for the residual axial load carrying capacity of RC columns under SFTCs employs a Bi-directional Long-Short-Term Model (BiLSTM) as the primary structure, Convolutional Neural Networks (CNN) for data preprocessing, and Squeeze-and-Excitation Networks (SE) to enhance the data preprocessing capability of CNN, yielding reference values for the residual axial load carrying capacity. Additionally, the simulation model is constructed in ABAQUS to support the data-theory driven prediction of the residual axial load carrying capacity of RC columns under SFTCs. The results demonstrate that the data-theory driven approach accurately predicts the failure modes of RC columns under SFTCs and achieves a prediction accuracy exceeding 93 % for the residual axial load carrying capacity. Consequently, this approach offers an efficient solution for predicting the degradation of the residual axial load carrying capacity of RC columns under SFTCs, reducing experimental costs and enhancing efficiency.</div></div>","PeriodicalId":10522,"journal":{"name":"Cold Regions Science and Technology","volume":"239 ","pages":"Article 104572"},"PeriodicalIF":3.8,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144254044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of embankment with reinforcement of New Geocell Soil System in cold regions","authors":"Hui Liu ,&nbsp;FuJun Niu ,&nbsp;Jun Hu","doi":"10.1016/j.coldregions.2025.104564","DOIUrl":"10.1016/j.coldregions.2025.104564","url":null,"abstract":"<div><div>Uneven displacement of permafrost has become a major concern in cold regions, particularly under repeated freezing-thawing cycles. This issue poses a significant geohazard, jeopardizing the safety of transportation infrastructure. Statistical analyses of thermal penetration suggest that the problem is likely to intensify as water erosion expands, with increasing occurrences of uneven displacement. To tackle the challenges related to mechanical behavior under cyclic loading, the New Geocell Soil System has been implemented to mitigate hydrothermal effects. Assessment results indicate that the New Geocell Soil System is stable and effective, offering advantages in controlling weak zones on connecting slopes and reducing uneven solar radiation. Consequently, the New Geocell Soil System provides valuable insights into the quality of embankments and ensures operational safety by maintaining displacement at an even level below 1.0 mm. The thermal gradient is positive, with displacement below 6 °C/m, serving as a framework for understanding the stability of the subgrade. This system also enhances stress and release the sealing phenomenon.</div></div>","PeriodicalId":10522,"journal":{"name":"Cold Regions Science and Technology","volume":"239 ","pages":"Article 104564"},"PeriodicalIF":3.8,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The indoor experimental method for the microseismic issue of freezing pipe fracture and its effectiveness verification","authors":"Yansen Wang ,&nbsp;Yi Cao ,&nbsp;Meng Zhao ,&nbsp;En Chen","doi":"10.1016/j.coldregions.2025.104573","DOIUrl":"10.1016/j.coldregions.2025.104573","url":null,"abstract":"<div><div>Artificial ground freezing technology is widely used in shaft construction in deep alluvial layers and water-rich soft rock layers. However, fractures in freezing pipes are difficult to completely eliminate. The leakage of brine caused by pipe rupture can easily trigger a degradation in the strength of the freezing wall, and even lead to flooding accidents in the well. To explore the feasibility of detecting and warning freezing pipe fractures through microseismic signals, this study constructs a physical model and experimental method for the vibration problem of freezing pipe fractures, based on the “frozen soil layer encapsulating freezing pipes (including joints)” structural type. Six types of frozen soil analog materials were first developed, with densities (2.0 g/cm³), elastic moduli (110–735 MPa), and compressive strengths (0.98–5.14 MPa) meeting the requirements for engineering frozen soil simulation. Subsequently, model freezing pipe fracture vibration tests were conducted under the encapsulation of frozen soil analog materials. The results indicate that under the constraint of frozen soil, as the radial dimension of the specimen increases, the main frequency of pipe rupture rises, while increasing the axial length leads to a decrease in the main frequency. When the radial size <em>D</em> = 7.5<em>D</em>₀ (where <em>D</em>₀ is the outer diameter of the freezing pipe) and the effective axial size reaches <em>H</em>₀ = 20<em>D</em>₀, the main frequency of pipe rupture tends to stabilize. By comparing the similarity criteria with the experimental results, the similarity of the freezing pipe fracture vibration problem and the reliability of the experimental method were validated. The research results lay the foundation for experimental studies and quantitative analysis of the vibration signal characteristics of freezing pipe fractures, establishing the experimental methodology and theoretical basis.</div></div>","PeriodicalId":10522,"journal":{"name":"Cold Regions Science and Technology","volume":"239 ","pages":"Article 104573"},"PeriodicalIF":3.8,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unconfined Compressive Strength (UCS) of frozen soil: A model considering temperature, moisture, and strain rate","authors":"Qin-long Liu ,&nbsp;Yong-kang Wu ,&nbsp;Li Liu ,&nbsp;Xu Li","doi":"10.1016/j.coldregions.2025.104545","DOIUrl":"10.1016/j.coldregions.2025.104545","url":null,"abstract":"<div><div>In the construction using the artificial ground freezing method, the strength of frozen soil is a critical parameter for calculating the thickness of frozen walls and for conducting safety assessments of frozen soil structures. Due to various factors such as temperature, soil type, water content, and strain rate, there is currently a lack of a unified understanding, especially regarding strength models that can consider multiple factors simultaneously. This study, through an extensive literature review, summarizes the influence and mechanisms of these factors on the strength of frozen soil. Results indicate that: (1) within the typical engineering temperature range, there is an approximately linear relationship between the compressive strength of frozen soil and temperature. The increase in ice strength and ice content due to lower temperatures are the primary reasons for the enhanced strength of frozen soil. (2) For unsaturated frozen soil, the compressive strength increases with increasing water content, whereas for saturated frozen soil, the strength decreases with increasing water content; overall, its compressive strength is positively correlated with ice content. (3) The compressive strength of frozen soil increases with higher strain rates, exhibiting a robust power function relationship between the two. Based on experimental data from the literature, a new multivariate strength model for frozen soil that considers temperature, saturation, and strain rate is proposed. Comparative analyses with existing models demonstrate that the new model offers greater adaptability and higher accuracy. This model provides an effective tool for characterizing and predicting the compressive strength of frozen soil, serving as a foundation for the engineering design and application of the artificial ground freezing method.</div></div>","PeriodicalId":10522,"journal":{"name":"Cold Regions Science and Technology","volume":"239 ","pages":"Article 104545"},"PeriodicalIF":3.8,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144291146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of droplet diameter on icing and aerodynamic characteristics of the inertial separator blade in marine environment","authors":"Yongpeng Ren,&nbsp;Chenliang Wang,&nbsp;Xiaohu Chen,&nbsp;Zhongyi Wang,&nbsp;Haiou Sun","doi":"10.1016/j.coldregions.2025.104565","DOIUrl":"10.1016/j.coldregions.2025.104565","url":null,"abstract":"<div><div>The low-temperature environment and sea spray in polar seas can cause ice accretion on the inertial separators in the intake systems of ships and coastal equipment, leading to blockages and seriously threatening the safe and efficient operation of the equipment. However, the icing characteristics of inertial separators in marine environments are not well understood, leading to a lack of design guidelines for corresponding anti-icing devices. This paper presents a numerical simulation of icing on inertial separator blades caused by saline droplets with varying Medium Volume Diameter (MVD) under marine conditions. The reliability of this method was verified through comparison with experimental data. The results show that increasing salinity significantly reduces the ice accretion on inertial separator blades. For MVD = 30 μm, increasing droplet salinity from 0.0 % to 3.5 % reduces the total blade icing area of simulation by 31.67 %. For MVD = 50 μm, the reduction is 28.12 %. Additionally, the rate of icing reduction increases with higher salinity. As the icing process progresses, the growth rate of blade icing gradually increases, but the rate of increase tends to slow down. As salinity increases, the total pressure loss of the blade after icing decreases, with larger droplets causing a greater reduction in pressure loss compared to smaller droplets. Increasing droplet salinity from 0.0 % to 3.5 % reduces total pressure loss by 10.51 % for MVD = 30 μm droplets and by 13.56 % for MVD = 50 μm droplets. This study provides fundamental theoretical data for the design of anti-icing devices for intake systems of ships and coastal equipment.</div></div>","PeriodicalId":10522,"journal":{"name":"Cold Regions Science and Technology","volume":"239 ","pages":"Article 104565"},"PeriodicalIF":3.8,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144231949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deformation mechanism and multilayer cooling strategy in a warm permafrost transition zone: The case study of a dry bridge along the Qinghai-Tibet Railway","authors":"Kun Chen ,&nbsp;Guoyu Li ,&nbsp;Qihao Yu ,&nbsp;Yanhui You ,&nbsp;Lei Guo ,&nbsp;Zhenyu Zhang ,&nbsp;Jinxin Lu","doi":"10.1016/j.coldregions.2025.104560","DOIUrl":"10.1016/j.coldregions.2025.104560","url":null,"abstract":"<div><div>Differential settlement and structural deformation in embankment-bridge transition zones (EBTZs) pose critical challenges to the operational safety of the Qinghai-Tibet Railway in warm permafrost regions. This study systematically investigates failure mechanisms through multidisciplinary field investigations (borehole drilling, geoelectrical surveys, geothermal monitoring), revealing that uneven permafrost degradation (ground temperatures: −0.3 °C to −0.1 °C) drives longitudinal differential settlement (max 130 cm), while coupled hydro-thermal erosion (soil moisture &gt;25 %) and frost heave exacerbate abutment deformations. To address limitations of traditional single-measure approaches, this study innovatively proposes a multilayer cooling strategy (MCS) integrating slope ventilation systems, horizontal thermosyphons (12-m evaporation sections), and foundation-targeted cooling units for multistage thermal regulation. Monitoring data demonstrate that MCS achieved permafrost table uplift of 3 m and elimination of settlement within two years, with ground temperatures stabilizing at −2 °C through multilayer thermal regulation. By decoupling hydrothermal interactions, MCS provides a novel solution for synchronous mitigation of thaw settlement and frost heave, offering practical insights for climate-resilient infrastructure in warming permafrost regions.</div></div>","PeriodicalId":10522,"journal":{"name":"Cold Regions Science and Technology","volume":"239 ","pages":"Article 104560"},"PeriodicalIF":3.8,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144242425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revealing the melting mechanism of segregated ice in frozen soil based on visualizing mass transfer dynamics","authors":"Zheng Wang ,&nbsp;Yaning Zhang ,&nbsp;Chi Zhang ,&nbsp;Bingxi Li","doi":"10.1016/j.coldregions.2025.104558","DOIUrl":"10.1016/j.coldregions.2025.104558","url":null,"abstract":"<div><div>The degradation of frozen soil structures caused by the melting of segregation ice plays a crucial role in initiating subgrade settlement. However, the researches on thawing frozen soil often overlooks the consideration of segregation ice and lacks effective approaches for its observation. In this study, a visualizing freezing-thawing platform was proposed to detail the thawing mechanism of segregated ice in frozen soil. The transient morphology of segregated ice and the variation of temperature, moisture content, melting ratio and settlement of frozen soil were explained based on the mass transfer dynamic. Meanwhile, the temperature-induced collapse of segregated ice layer pores is revealed as a key contributor to thawing settlement, and this chain reaction is proposed as a novel explanation based on the measurements obtained from visualizing platform. The results shows that based on dynamic observations of morphology, the segregated ice undergoes a process of small bubble formation, growth, coalescence and leaving behind pores during melting. Raising the temperature of the upper surface from 5 °C to 10 °C significantly shortened the melting time for segregated ice, cutting it down from 3.7 h to just 1.8 h. As the particle sizes decreased from G-I (0.150 mm) to G-V (0.013 mm), there was a rise in the moisture content from 0.16 to 0.21, while the increase in external load from 0.5 kg to 1.5 kg resulted in a rise in settlement from 1.1 mm to 2.1 mm.</div></div>","PeriodicalId":10522,"journal":{"name":"Cold Regions Science and Technology","volume":"239 ","pages":"Article 104558"},"PeriodicalIF":3.8,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144221052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation on frost heave characteristics of red-stratum mudstone for HSR subgrade based on the orthogonal array testing","authors":"Yuteng Qin ,&nbsp;Guoqing Cai ,&nbsp;Qianqian Liu ,&nbsp;Yanlin Su ,&nbsp;Jian Li","doi":"10.1016/j.coldregions.2025.104559","DOIUrl":"10.1016/j.coldregions.2025.104559","url":null,"abstract":"<div><div>The current research concerning the frost heave characteristics of red-stratum mudstone is little. The frost susceptibility of red-stratum mudstone will increase due to the intervention of fine particles and water when used as high-speed railway (HSR) subgrade fillers, resulting in uneven frost heave and damage during the cold season. Several L₉(4³) unidirectional freezing orthogonal experiments, using dry density, water content, and the step cooling path as factors, were conducted in open and closed systems. The analytic hierarchy process (AHP) was used to analyze the influence weights of the experimental factors on the frozen depth and frost heave ratio. The results showed that water content and dry density more substantially affect the frost heave ratio. The step cooling path plays a dominant role in the penetration of frozen depth, and water supplement decreased the penetration of frozen depth in the open system. Moisture in the unfrozen zone migrated toward the frozen zone. Red-stratum mudstone is highly susceptible to frost heave, with frost heave ratio easily exceeding 1 % and maximum value approaching almost 5 %.</div></div>","PeriodicalId":10522,"journal":{"name":"Cold Regions Science and Technology","volume":"238 ","pages":"Article 104559"},"PeriodicalIF":3.8,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}