scholarly journals Failure Patterns and Morphological Soil–Rock Interface Characteristics of Frozen Soil–Rock Mixtures under Compression and Tension

2021 ◽  
Vol 11 (1) ◽  
pp. 461
Author(s):  
Feng Hu ◽  
Zhiqing Li ◽  
Yifan Tian ◽  
Ruilin Hu
Keyword(s):  
Crack Path ◽  
Frozen Soil ◽  
Failure Pattern ◽  
Rock Block ◽  
Foundation Engineering ◽  
Construction Operations ◽  
Cold Regions ◽  
Failure Patterns ◽  
Indirect Tension ◽  
Rock Interface

Construction operations in cold regions may encounter frozen geomaterials. In construction, it is important to understand the processes by which geomaterials fail under common loading conditions to avoid accidents and work efficiently. In this work, an artificial frozen soil–rock mixture was used for uniaxial compression and indirect tension loading analysis to investigate macroscopic failure patterns and soil–rock interface crack evolution mechanisms. To further understand and compare the meso-mechanical failure mechanisms of the soil–rock interface, we used two types of rock block particles with different surface roughness for fabricating frozen artificial soil–rock mixtures. Acoustic emission (AE), ultrasonic plus velocity (UPV), and digital microscopy were utilized here to obtain the sample deformation response and analyze the morphology of the soil–rock interface. The results were as follows. From the perspective of macroscopic observation, bulging deformations and short tension cracks represent the main failure pattern under compression, and a tortuous tension crack in the center of the disk is the main failure pattern under indirect tension. From the perspective of microscopic observation, the soil–rock interface will evolve into a soil–rock contact band for the sample containing a rough rock block. The strength of the soil–rock contact band is obviously larger than that of the soil–rock interface. Three main failure patterns of the soil–rock interface were observed: a crack path through the accurate soil–rock interface, a crack path through the envelope of the rough rock block, and a crack path passing through the rough rock block. The experimental results could provide a reference for foundation engineering, especially in pile foundation engineering in cold regions.

scholarly journals Simulating cold-region hydrology in an intensively drained agricultural watershed in Manitoba, Canada, using the Cold Regions Hydrological Model

2017 ◽  
Vol 21 (7) ◽  
pp. 3483-3506 ◽  
Author(s):  
Marcos R. C. Cordeiro ◽  
Henry F. Wilson ◽  
Jason Vanrobaeys ◽  
John W. Pomeroy ◽  
Xing Fang ◽  
...  
Keyword(s):  
Preferential Flow ◽  
Model Development ◽  
Agricultural Watershed ◽  
Frozen Soil ◽  
Red River ◽  
Hydrological Processes ◽  
Low Flow ◽  
Northern Great Plains ◽  
Agricultural Watersheds ◽  
Cold Regions

Abstract. Etrophication and flooding are perennial problems in agricultural watersheds of the northern Great Plains. A high proportion of annual runoff and nutrient transport occurs with snowmelt in this region. Extensive surface drainage modification, frozen soils, and frequent backwater or ice-damming impacts on flow measurement represent unique challenges to accurately modelling watershed-scale hydrological processes. A physically based, non-calibrated model created using the Cold Regions Hydrological Modelling platform (CRHM) was parameterized to simulate hydrological processes within a low slope, clay soil, and intensively surface drained agricultural watershed. These characteristics are common to most tributaries of the Red River of the north. Analysis of the observed water level records for the study watershed (La Salle River) indicates that ice cover and backwater issues at time of peak flow may impact the accuracy of both modelled and measured streamflows, highlighting the value of evaluating a non-calibrated model in this environment. Simulations best matched the streamflow record in years when peak and annual discharges were equal to or above the medians of 6.7 m3 s−1 and 1.25  × 107 m3, respectively, with an average Nash–Sutcliffe efficiency (NSE) of 0.76. Simulation of low-flow years (below the medians) was more challenging (average NSE  <  0), with simulated discharge overestimated by 90 % on average. This result indicates the need for improved understanding of hydrological response in the watershed under drier conditions. Simulation during dry years was improved when infiltration was allowed prior to soil thaw, indicating the potential importance of preferential flow. Representation of in-channel dynamics and travel time under the flooded or ice-jam conditions should also receive attention in further model development efforts. Despite the complexities of the study watershed, simulations of flow for average to high-flow years and other components of the water balance were robust (snow water equivalency (SWE) and soil moisture). A sensitivity analysis of the flow routing model suggests a need for improved understanding of watershed functions under both dry and flooded conditions due to dynamic routing conditions, but overall CRHM is appropriate for simulation of hydrological processes in agricultural watersheds of the Red River. Falsifications of snow sublimation, snow transport, and infiltration to frozen soil processes in the validated base model indicate that these processes were very influential in stream discharge generation.

An Analytical Model to Predict the Push-Out Capacity of Mortar from Rock Block

2011 ◽  
Vol 250-253 ◽  
pp. 2396-2406
Author(s):  
Shu Tong Yang
Keyword(s):  
Analytical Model ◽  
Interfacial Shear Stress ◽  
Tensile Load ◽  
Interfacial Shear ◽  
Rock Block ◽  
Ground Anchors ◽  
Proposed Model ◽  
Wide Range ◽  
Rock Interface ◽  
Push Out

Ground anchors have been very practical in a wide range of geotechnical structures. Good bond properties at the anchor-mortar and mortar-rock interfaces can ensure transmitting an applied tensile load to a load bearing structure efficiently. The bond performance between the mortar and rock is necessary to be studied. A push-out test of mortar from rock block can be used to analyze the interfacial properties between the two materials. In this paper, an analytical model is proposed to determine the push-out capacity of mortar from rock block. Based on the deformation compatibility at the interface, the compressive stress in the mortar and the interfacial shear stress at the mortar-rock interface are formulated at different loading stages. By modeling interfacial debonding as an interfacial shear crack, the push-out load is then expressed as a function of the interfacial crack length. In virtue of the Lagrange Multiplier Method, the maximum push-out load is determined. The validity of the proposed model is verified with the experimental results. It can be concluded that if the interfacial parameters at the mortar-rock interface are obtained, the push-out capacity of mortar from rock block can be accurately determined using the proposed model. The proposed solution in this paper would provide a good theoretical basis in evaluating the stability of ground anchors in practice.

scholarly journals Elastic Modulus Calculation Model of a Soil-Rock Mixture at Normal or Freezing Temperature Based on Micromechanics Approach

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Hao Yang ◽  
Zhong Zhou ◽  
Xiangcan Wang ◽  
Qifang Zhang
Keyword(s):  
Composite Material ◽  
Elastic Modulus ◽  
Freezing Temperature ◽  
Calculation Model ◽  
Frozen Soil ◽  
Experimental Comparison ◽  
Mesoscopic Structure ◽  
Embedded Model ◽  
Single Inclusion ◽  
Rock Interface

Considering rock wrapped by soil in the mesoscopic structure of soil-rock mixture at normal temperature, a two-layer embedded model of single inclusion composite material was established to obtain the elastic modulus of soil-rock mixture. Given an interface ice interlayer attached between the soil and rock interface in the mesoscopic structure of soil-rock mixture at freezing temperature, a three-layer embedded model of double inclusion composite material and multistep multiphase micromechanics model was established to obtain the elastic modulus of a frozen soil-rock mixture. With the effect of structure pore with soil-rock mixture at normal temperature taken into consideration, its elastic modulus was calculated with the three-layer embedded model. An experimental comparison found that the predicted effect of the three-layer embedded model on the soil-rock mixture was better than that of the two-layer embedded model. The elastic modulus of soil-rock mixture gradually increased with the increase in rock content regardless of temperature. The increase rate of the elastic modulus of the soil-rock mixture increased quickly especially when the rock content is between 50% and 70%. The elastic modulus of the frozen soil-rock mixture is close to four times higher than that of the soil-rock mixture at a normal temperature.

Wear Out Failure Patterns and Their Interpretation

1980 ◽  
Vol 22 (3) ◽  
pp. 143-151 ◽  
Author(s):  
A. D. S. Carter
Keyword(s):  
Fatigue Strength ◽  
Failure Rate ◽  
Initial Period ◽  
Failure Pattern ◽  
Weibull Distributions ◽  
Increasing Failure Rate ◽  
Failure Patterns ◽  
Loss Of Strength ◽  
Continuous Loss

It is shown theoretically that fatigue of a component will result in a failure pattern which consists of an initial period of intrinsic reliability, or near zero failures, followed by a rapid increase in failure rate when loss of fatigue strength becomes operative, to be followed in turn by a period during which the failure rate decreases with time or maybe remains constant. By contrast other wear-out modes involving a continuous loss of strength give rise to a steadily increasing failure rate after the period of intrinsic reliability has expired. Practical examples of each type are quoted to substantiate the theoretical deductions. The interpretation of wear out characteristics by Weibull distributions is discussed.

scholarly journals MECHANISMS OF COASTAL DIKE FAILURE INDUCED BY THE GREAT EAST JAPAN EARTHQUAKE TSUNAMI

2012 ◽  
Vol 1 (33) ◽  
pp. 40 ◽  
Author(s):  
Fuminori Kato ◽  
Yoshio Suwa ◽  
Kunihiro Watanabe ◽  
Satoshi Hatogai
Keyword(s):  
Hydraulic Model ◽  
Great East Japan Earthquake ◽  
Failure Pattern ◽  
Field Surveys ◽  
Model Experiments ◽  
Failure Patterns ◽  
Dike Failure

Based on the results of field surveys, coastal dike failures caused by the Great East Japan Earthquake were classified into eight patterns. The results of hydraulic model experiments related to major failure patterns reinforced the proposed failure processes. In addition, the aggregated length of each failure pattern showed that failure from scouring at the landward toe is the dominant failure pattern.

scholarly journals ANALISIS DAKTILITAS BALOK BETON GRADASI DENGAN DISPARITAS MUTU BETON SERAT TEKAN DAN SERAT TARIK

BANGUNAN ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 17
Author(s):  
M. Mirza Abdillah Pratama ◽  
Ziana Nur Afdila ◽  
Karyadi Karyadi
Keyword(s):  
Carbon Dioxide Emissions ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Maximum Load ◽  
Cement Industry ◽  
Failure Pattern ◽  
Beam Deflection ◽  
Uniform Compression ◽  
Failure Patterns

Abstrak: Industri semen menyumbang hingga 8% dari seluruh emisi gas karbon dioksida secara global. Beton gradasi merupakan salah satu langkah untuk mereduksi penggunaan semen pada konstruksi sekaligus untuk mengoptimalkan karakteristik mekanik elemen struktur yang direncanakan. Penelitian ini bertujuan untuk menganalisis capaian beban maksimum, defleksi, kekakuan, daktilitas, dan pola kegagalan dari balok beton gradasi dengan variasi mutu beton pada serat tekan dan serat tariknya. Balok Balok gradasi terbuat dari perpaduan antara 2 (dua) campuran mutu yang berbeda, yaitu 30-40 MPa, 30-50 MPa, dan 40-50 MPa. Pengujian lentur balok beton dilakukan pada umur 28 hari. Pola kegagalan pada balok beton gradasi pada masing-masing benda uji diamati dan dikomparasikan dengan balok beton kontrol. Hasil pengujian menunjukkan bahwa balok beton gradasi dengan mutu beton pada serat tarik yang seragam menghasilkan beban, kekakuan, dan daktilitas balok yang lebih tinggi seiring peningkatan mutu beton yang digunakan pada serat tekannya. Balok dengan mutu beton serat tekan seragam dan serat tarik yang berbeda memiliki nilai capaian beban, kekakuan, dan daktilitas balok yang semakin besar seiring peningkatan mutu beton pada bagian serat tarik balok. Lendutan balok yang dihasilkan masih memenuhi lendutan izin. Berdasarkan hal tersebut, balok beton gradasi dinyatakan memiliki kemampulayanan yang baik.Kata-kata kunci: Balok Beton Gradasi, Kekakuan, Daktilitas, Pola KegagalanAbstract: The cement industry accounts for up to 8% of all global carbon dioxide emissions. Graded concrete is one of the steps to reduce the use of cement in construction as well as to optimize the mechanical characteristics of the planned structural elements. This study aims to analyze the maximum load performance, deflection, stiffness, ductility, and failure patterns of graded concrete beams with variations in the quality of concrete in the compression fiber and tensile fiber. Gradation beams are made from a combination of 2 (two) different quality mixtures, namely 30-40 MPa, 30-50 MPa, and 40-50 MPa. The flexural testing of the concrete beams was carried out at the age of 28 days. The failure pattern of the graded concrete beams for each test object was observed and compared with the control concrete beams. The test results show that graded concrete blocks with uniform tensile strength of concrete produce higher beam loads, stiffness, and ductility as the quality of the concrete used in compression fibers increases. Beams with uniform compression fiber and different tensile fibers have higher load, stiffness, and ductility values as the concrete quality increases in the tensile fiber portion of the beam. The resulting beam deflection still meets the allowable deflection. Based on this, the graded concrete beam is declared to have good serviceability.Keywords: Graded Concrete Beam, Stiffness, Ductility, Failure Pattern

scholarly journals Analysis of main points of channel freezing-thawing disease in cold region and influence of channel base soil on the disease

2021 ◽  
Vol 329 ◽  
pp. 01090
Author(s):  
Liqing Liang
Keyword(s):  
North China ◽  
Hydraulic Structure ◽  
Research Direction ◽  
Frozen Soil ◽  
Frost Heave ◽  
Cold Region ◽  
Freezing And Thawing ◽  
Cold Regions ◽  
Seasonal Frozen Soil ◽  
Base Soil

The frozen soil area in China is more than two thirds of the total territory, so the problem of frost heave is obvious. Especially in northeast, northwest, north China and other cold regions, the problem of frost heave of hydraulic structures is very common. Canal is a common hydraulic structure in agricultural water, which is affected by seasonal frozen soil and may cause problems such as lining damage, seepage and irrigation efficiency. Therefore, this paper mainly summarizes the necessity of research on channel freezingthawing damage, the research direction of channel freezing-thawing damage, and expounds the influence of seasonal frozen soil on freezing and thawing diseases in cold regions by taking the particle size of saturated soil based on channel as an example.

scholarly journals A Modified ABCD Model with Temperature-Dependent Parameters for Cold Regions: Application to Reconstruct the Changing Runoff in the Headwater Catchment of the Golmud River, China

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1812
Author(s):  
Xiaoshu Wang ◽  
Bing Gao ◽  
Xusheng Wang
Keyword(s):  
Groundwater Level ◽  
Hydrological Model ◽  
Cold Season ◽  
Annual Runoff ◽  
Frozen Soil ◽  
Washington Dc ◽  
Temperature Dependent ◽  
Cold Regions ◽  
Monthly Runoff ◽  
Headwater Catchment

The runoff changes due to global warming in hydrological basins in the Qinghai–Tibetan Plateau (QTP) have received worldwide attention. The headwater catchment of the Golmud River, located in the northern QTP, is the main source of water resources for the Golmud city in an arid region but has been poorly known for the hydroclimatological behaviors. In this study, a widely-used hydrological model, the ABCD model (Thomas, H.A., Washington, DC, USA), is modified by incorporating temperature-dependent hydrological processes and groundwater evapotranspiration in cold regions with a few additional parameters. The new model is used to reconstruct the monthly runoff in the past decades for the headwater catchment of the Golmud River and performs better than other comparable models. As indicated, the annual snowmelt runoff increased with the increasing air temperature and became more concentrated in April than in May. The frozen soil degradation could increase the hydraulic conductivity of soils and lead to a rise in cold season runoff. The groundwater level in the Golmud city was positively correlated to the annual runoff in the headwater catchment of the Golmud River, indicating that an increase of the groundwater level could be triggered by the rising trend in the streamflow of the Golmud River. This study suggests a useful hydrological model for the groundwater management in the Golmud city.

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