The super-dense sand layer is distributed in the buried depth of 16～23 m in the Xinyi district.The parameters of the prefabricated pile foundation are usually taken according to the empirical method of the technical code for building pile foundation,and the static load test of the destructive test pile is generally not carried out.The design of the pile foundation is too dense,which aggravates the difficulties of pile sinking,pile upwelling,pile resistance loss and other pile foundation construction problems.Based on the static load test,through the back analysis of the ultimate tip resistance qpk of the single pile in the super dense sand layer,the value interval of qpk of the super-dense sand layer is preliminarily given,which provides some reference for the pile foundation parameter suggestion and pile foundation optimization design when the super-dense sand layer is used as the bearing layer of the prefabricated pile tip.
Accurate regional evaluation results of geological hazard susceptibility can provide reference for the establishment of geological hazard monitoring and early warning system and treatment mechanism.According to the formation conditions of geological disasters,ten evaluation factors were selected to construct an evaluation index system,and the evaluation factors were tested based on collinearity diagnosis and correlation analysis to ensure their independence.The susceptibility of landslide geological disasters in Luoping County was evaluated by information information model(ICM),normalized frequency ratio model(NFR),information information-logistic regression(ICM-LR)coupled with logistic regression(LR)and normalized frequency ratio logistic regression(NFR-LR)coupled model,the results of the evaluation model were divided into four grades:low,medium,high and extremely high.ROC curve was used to test the accuracy of the evaluation results,and the AUC values were 0.820,0.796,0.882 and 0.840,respectively.The results show that the ICM-LR model has the highest accuracy,and the highly susceptible areas are mainly distributed in the sandstone,carbonate formation area and drainage extension area.The low,middle,high and very high area(grading ratio)are 771.1km,respectively2(25.55％),836.6 km2(27.73％),864.36 km2(28.64％)and 545.94 km2(18.08％).The results of susceptibility zoning are consistent with the distribution of landslide geological hazards in the study area,which can provide a reference for the rapid establishment of evaluation index system and regional landslide susceptibility evaluation model.
Dongge Highway and S209 Line are located in the Xiaojiang River Basin in Yunnan Province,and they pass through the debris flow area.The debris flow is large in scale and highly active,posing a growing threat to highway bridge and culvert structures.Based on the preliminary data collection and field investigation,the impact of debris flow gullies along the line on highway bridge and culvert structures is analyzed,and the comprehensive prevention and control measures for highway debris flow areas are proposed.The results show that the debris flow disaster is harmful to highway structures.The bridge and culvert damage mainly occurs in the form of erosion,abrasion and local siltation.The local foundation(conical slope)and bridge(culvert)abutment are damaged by erosion,scouring,erosion and siltation.The research results have important reference value for strengthening the design and prevention of subgrade,bridge and culvert and other structures in highway debris flow area.
Geological hazards are prevalent in the Hengduan Mountains,Landslide disaster is one of the most development-prone and harmful disasters,in addition,mountainous towns and villages have complex terrain environments and more irregular activities,which are easy to cause landslides.Therefore,it is of great significance to assess the landslide susceptibility of rural townships in this region.Taking the Ankang Wa ethnic township in Lancang County,Pu'er City as an example,this study established an evaluation index system for landslide susceptibility using eight influencing factors such as elevation,slope,aspect,and relief.The hierarchical structure of landslide susceptibility evaluation indicators for small-scale areas was constructed.The Analytic Hierarchy Process(AHP)was used to determine the weight values of each factor.Based on the Comprehensive Vulnerability Index method,the landslide vulnerability of the study area was evaluated using ArcGIS spatial analysis.Four categories of regions were identified:high vulnerability area with an area proportion of 14.53％,relatively high vulnerability area with an area proportion of 34.06％,medium vulnerability area with an area proportion of 33.57％,and low vulnerability area with an area proportion of 17.84％.It provides reference for disaster prevention and reduction and landslide disaster control in Ankang Wa Nationality Township,and also provides ideas and methods for small regional landslide disaster susceptibility evaluation.
In this paper,the MJ053 landslide of the Baise-kunming oil product pipeline located in Jianshui County,China,is taken as the object of analysis,the formation mechanism and stability of the landslide under the action of rainfall are studied by using the numerical simulation method combined with the percolation theory of unsaturated soil,and the stability change of the landslide under the action of the continuous heavy rainfall for three days is analyzed.The results show that the landslide is obviously affected by heavy rainfall.Under the condition of extreme heavy rainfall,the displacement of the landslide soil increases rapidly in a short time,and the stability of the landslide decreased to an unstable state,and the landslide must be treated.
Cataclastic rock mass,as a type of rock mass with complex structure and weak strength,is usually treated as a weak zone in engineering practice.In order to explore the engineering characteristics of cataclastic rock mass,starting from the physical-mechanical properties of cataclastic rock mass,this study employs self-developed in-situ sampling technology to conduct an in-depth analysis of physical indicators such as particle size composition,density,and porosity of fractured rock masses in different power stations under in-situ conditions.Gongboxia Hydropower Station was taken as the research object to conduct indoor equivalent compaction tests.By comparing the results of sediment compaction tests and in-situ physical parameter measurements at home and abroad,it has been successfully verified that indoor equivalent compaction tests can obtain the same physical and mechanical indicators as in-situ stress situation.
In order to study the development law of lethal geological disasters in Jiangxi Province in recent years,the development characteristics of 45 lethal geological disasters and the characteristics of their bearing bodies were studied by using the survey data of lethal geological disasters in Jiangxi Province from 2013 to 2022 and statistical analysis methods.The geological disasters in Jiangxi Province are characterized by small scale,large quantity,great harm and rainstorm;Geological hazards are mostly developed in soil slopes,and engineering slope cutting is an important triggering factor of geological hazards;Geological disasters rarely cause total damage to houses,and in most cases only cause back wall collapse or partial damage;The role of personal ability in avoiding geological disasters is not obvious;The victims are most likely to die when they sleep,and local damage to the house may cause death.
Puxian Township landslide is located in Puxian Township,Guangyuan City,Sichuan Province.In order to solve the property loss and security threat caused by the landslide,a large number of studies have been carried out based on the topography and basic characteristics of the landslide area.In this paper,the limit equilibrium method is used to study the stability of landslide in Puxian township.The calculation results show that the landslide is in a stable state under natural and seismic conditions,and in an under stable state under heavy rain conditions.The prevention and control measures of ditch modification and slag back filling project+anti-slide pile+tensile crack sealing are proposed.
The community of life consisting a full range of ecosystems is an important part of modern ecological conservation.This study focuses on the ecological demonstration zone in Aba Prefecture,northwest Sichuan,investigating the current ecological environment and the impact of human activities.Through comprehensive surveys,the study specifically examines the ecological conservation measures and restoration techniques for water environment,grassland,and mining areas.The results show that the main ecological issues in northwest Sichuan's Aba Prefecture include environmental degradation,soil erosion,and forest destruction,with human engineering activities being the primary factors influencing the ecological environment.Strict water resource management measures and policies addressing water pollution form the foundation for water environment ecological protection.Effective restoration of grassland water quality can be achieved through the construction of wetland treatment areas,ecological floating islands,and the use of reclaimed water for supplementation.Measures for land treatment in mining subsidence areas and vegetation restoration are proposed,with monitoring for reclamation being an essential means of evaluating mining environmental restoration effectiveness.The findings of this study provide theoretical and technical support for the overall protection,systematic restoration,and comprehensive management of the community of life consisting a full range of ecosystems.
The groundwater in an oil refinery area in Yunnan is taken as the research object,and the hydrogeological model is established by analyzing its hydrogeological conditions and combining with water level information of boreholes.Petroleum species were selected as predictors,and the groundwater flow field model and solute transport model were established using GMS software.Calculate the migration process of petroleum species in(156)days,and compare the three pump-and-treat method prevention and control management options to select the optimal one.The results of the study showed that JC02 monitored pollutants when the oil continued to leak for 156 days,and the combination of economic and human factors scheme ② was optimal.
Based on field investigation and laboratory simulation,the evolution process of landslide and debris flow and the change of matric suction were analyzed in the terraced fields of Yuanyang County,China,research on the disaster-causing model of disaster chain.Three groups of tests were carried out under two working conditions,among which the rainstorm test was carried out twice,and the one with better test results was selected for analysis.The results show that the process of landslide and debris flow disaster chain is very complex,and the surface water flow velocity will decrease gradually after the large amount of debris on the slope surface is exposed by rainfall,which is more advantageous to the infiltration of surface water,due to the continuous heavy rainfall,the slope of terraced field slides and then evolves into debris flow which continues to move along the terraced field,compared with the continuous heavy rain,the time of landslide induced by continuous moderate rain is longer,and the destructive force of landslide is smaller than that of heavy rain,the latter has a larger impact area,and the disaster-causing degree varies greatly in different regions.
The types of geological hazards in Daguan County,Yunnan Province are mainly landslides,collapses,and debris flows.According to the latest detailed survey and risk assessment of Yunnan Province,a total of 567 geological disasters were found in Daguan County,203 new disaster compared with the 1∶50 000 detailed survey in 2015.Including 299 landslides,210 collapses,56 debris flows and 2 ground subsidence.With the help of spatial analysis technology of geographic information system(GIS),combined with the latest refined survey results of geological disasters and the data of the third national land survey,using the analytic hierarchy process(AHP)and the information computation method to assess the risk of geological disasters and zone in Daguan County,Yunnan Province.The research results can provide a basis for the prevention and control of geological hazards and the risk management of geological hazards in Daguan County,Yunnan Province.
In order to summarize the geological hazard breeding law of Meitan County and guide the geological hazard prevention project of Meitan County.Based on the analysis of the development characteristics of the current geological hazard and the geological hazard preparation factors,the paper analyzes the slope,geological structure,rock and soil mass type,slope structure,surface water factors and groundwater factors,and uses the ARCGIS software to carry out disaster preparation zoning.The whole county is divided into pregnancy prone geological hazard areas,moderate pregnancy prone geological hazard areas and general pregnancy prone geological hazard areas,and corresponding prevention and treatment suggestions are provided for the management and control of unreasonable slope cutting in different districts,the publicity and training of geological hazard,the investigation and early warning monitoring of geological hazard and risky slopes.
In order to effectively prevent and control geological disasters,reduce the occurrence and damage of geological hazards in Fujian province,based on the geological disasters data of Fujian province in 2010,2015 and 2020,the article uses GIS overlay analysis method to quantitatively analyze the spatiotemporal distribution characteristic of geological hazards in Fujian province under different conditions such as topography,rock lithology,land use type,water system,road network,etc.The results showed that:(1)The number of geological disasters in Fujian province was declining year by year,and they were mainly distributed in LongYan,NanPing and NingDe.(2)During the study period,geological disasters in Fujian province were mainly distributed in high hills,low mountains,low slopes and northeast areas..The distribution of geological hazard density on rock lithology varied greatly in different years.(3)Geological hazards are mostly distributed in shrub forests,construction land and bare land,and areas with strong human engineering activities such as road networks and water systems.
Due to the extraction of underground water and the engineering construction,land subsidence is widely distributed in the worldwide plains.The cities will lose their elevation because of the settlement which enlarge the economic damages and loss of lives in flood disasters.The surface deformation in Ningbo plain from 2017 to 2021 was obtained by using PS-InSAR(Persistent Scatterer Interferometric Synthetic Aperture Radar)technique based on 60 pieces of Sentinel-1 images,the precision and reliability of the deformation were verified by the leveling data in the same period.The results showed the engineering construction was the major factor resulting in the land subsidence in Ningbo at the present stage.Besides,the settlement in coastal reclamation area such as Hangzhou Bay New Area was significantly related to the time of reclamation and engineering construction.At last,the land subsidence in urban built-up area was limited in the recent engineering construction area and the settlement rate would decelerate rapidly.
Based on the hydrogeological conditions of the study area,the solute transport model of ammonia nitrogen pollutants under convection and dispersion was established by using GMS to simulate and predict the physical location characteristics and migration law of ammonia nitrogen at 1000 d,3000 d and 5000 d.The results show that in the process of ammonia nitrogen transport in groundwater,the halo of pollution with different concentrations The results show that the pollution halo of different concentrations of ammonia nitrogen is symmetrically distributed with high concentration as the center,and its concentration content gradually decreases from the center to the edge,which indicates that the ammonia nitrogen is slowly transported with the groundwater under the convection and dispersion effects.
In the early morning of August 17,2020,a massive debris flow occurred in Jiawu gully.Mudslides have severely blocked the Tangzhu River.The main river water and Jiawu gully debris flow formed the potential of overflow.The river carries a large amount of mud sand and gravel,silt buried in the gully mouth downstream of Yangshan village resettlement site and Wujiao town.After field investigation and measurement of multiple debris flow cross sections.The motion characteristic parameters of"8.17"debris flow are calculated and analyzed,the intensity of debris flow on"8.17"was close to the intensity of debris flow with rainfall intensity of once in 10 years,the nature of debris flow is rare debris flow.Loose solids are abundant in Jiawu gully debris flow,easy to cause the main river Tangzhu blocked.Calculated according to the discriminant formula of debris flow blocking river,mudslides are likely to block the Tangzhu River.
This paper takes a red layer hilly area in Chengdu as the research object,and considers the influence of"infiltration,storage and purification"of sponge city construction,and considers that the main geological influencing factors of sponge city construction in red layer hilly area include slope,geotechnical permeability,sub-bedding surface condition,thickness of quaternary cover layer,depth of buried water table,distribution of water system,vegetation The influence of slope,quaternary cover thickness and geotechnical permeability on sponge city construction was finally determined through on-site investigation and implementation of corresponding permeability tests.Subsequently,the weight values of each factor were determined,the evaluation system was constructed,and the geological suitability zoning for sponge city construction in the study area was determined to provide the theoretical basis for the later planning related to sponge city construction in other red layer hilly areas.
In order to study the physical and mechanical properties of basalt residual clay widely distributed in Tengchong area,The relevant test parameters were obtained through indoor geotechnical tests such as specific gravity test,moisture content test,consolidation test and field in-situ test,and indoor theoretical analysis was carried out.The results show that the chemical components of basalt residual soil in Tengchong area are mainly SiO2,Al2O3 and Fe2O3;The water content of basalt residual clay is between 14％～95％,the average value is 49.44％,the void ratio is between 0.48～2.56,the average value is 1.44,the saturation is between 46～100,the average value is 92.52,the wet density is between 1.36～2.13,the average value is 1.68;The compressibility coefficient ai-2 is 0.67 MPa-1,which belongs to highly compressible soil.The soil structure is loose,the physical and mechanical properties vary greatly in space,the cohesion is 40.13 kPa,and the internal friction angle 7.44 °,the strength is relatively low.
土壤盐分与盐渍化的特征和时空分布特征研究,对土壤盐渍化防治和土壤开发利用十分重要.根据在青铜峡灌区布设的80个代表性土壤样点0～60 cm分层取样测定的土壤全盐量数据,采用经典统计学、地质统计学,结合GIS技术研究灌区春灌前土壤全盐量、主要化学组分特征与盐渍化空间分布格局.结果表明:①青铜峡灌区不同深度土壤全盐量呈偏态分布且都属强变异强度;土壤全盐量与主要盐分离子均存在极显著正相关关系(P＜0.01);阴阳离子间的强相关性反映出不同深度土壤盐分阴阳离子组合十分复杂.②不同深度土壤全盐量和K++Na+、Cl-、SO2-4、HCO-3含量具有中等-较强烈的空间自相关性,最大自相关距离均未超过灌区最大直线范围的1/3.③灌区0～20 cm土壤属于非、轻度、中度、重度盐化土和盐土的面积分别是437.68 km2、615.43 km2、650.00 km2、2033.27 km2、2419.70 km2;随土壤深度增加重度盐化土和盐土面积明显减少.K++Na+、Cl-、SO2-4、HCO-3含量的空间分布与土壤全盐量相似.总体来说,青铜峡灌区春灌前土壤盐渍化现象依然严重且复杂,应加强研究治理.
