This study explores an alternative to the classical use of direct methods, as water content and dry density measurements, for compaction quality control. For this purpose, the dielectric properties of lateritic materi...This study explores an alternative to the classical use of direct methods, as water content and dry density measurements, for compaction quality control. For this purpose, the dielectric properties of lateritic materials are determined by radar method and are compared with the permittivity determined from the Topp formula and from the CRIM model. This approach allowed to establish a relationship between the geotechnical properties determined during compaction such as dry density, water content or porosity with dielectric permittivity. The obtained results made it possible to determine an optimum dielectric permittivity corresponding to the optimum dry density and the optimum water content that could be used for non-destructive in situ compaction testing. Such an approach should improve the implementation and effectiveness of in situ compaction quality control of geotechnical infrastructures.展开更多
Background: COVID-19 limitations have hindered the implementation of new technologies by preventing proctors from coming to the site.We share our first experience of magnetic resonance imaging(MRI)-guided focused ultr...Background: COVID-19 limitations have hindered the implementation of new technologies by preventing proctors from coming to the site.We share our first experience of magnetic resonance imaging(MRI)-guided focused ultrasound(MRgFUS)treatment with an international remote online proctorship,and develop and evaluate the methodology of remote MRgFUS proctorship.Methods: This single-center,nonrandomized controlled prospective study included 94 patients:27 with essential tremor(ET)and 67 with tremor-dominant Parkinson's disease(PD).The coming of proctors was impossible,so we arranged for the remote participation of proctors from the United Kingdom,Spain,and Israel.A total of 38 patients(40.4%)received telemedicine-proctored treatment(proctor group)and 56 received their treatment independently(solo group).We used the Clinical Rating Scale for Tremor(CRST)for ET patients and the Unified Parkinson's Disease Rating Scale(UPDRS)Part III for PD patients.Results: In patients with ET,success rates were 81.8%(proctor group)and 100%(solo group)(p=0.22).CRST reduction on the treated side was 71.43%[65.83%;80.56%](proctor group)versus 60.87%[53.99;79.58](solo group)(p=0.19).None of the patients showed worsening of tremors within 1 year.In patients with PD,the success rates were 92.6%(proctor group)and 100%(solo group)(p=0.08).The UPDRS Part III improvement was 30.1%(proctor group)versus 39.9%(solo group)(p=0.003).The 1-year recurrence rate was 40%(proctor group)and 17.5%(solo group)(p=0.04).No complications were observed at 6 months.Conclusions: We developed a feasible and safe methodology for telemedicine remote online-proctored MRgFUS treatment.No significant difference was observed between the solo and developed remote proctor protocols in terms of complication rate,effect,and long-term results;however,UPDRS Part III improvement was better in the PD solo group.This study demonstrated that the MRgFUS international proctorship can be performed successfully remotely.展开更多
Most of the laterites found in Ivory Coast do not meet the technical conditions to be used in their natural state for the design of road foundations. Also, to meet the growing needs for road materials, various amendme...Most of the laterites found in Ivory Coast do not meet the technical conditions to be used in their natural state for the design of road foundations. Also, to meet the growing needs for road materials, various amendments are made to them, including litho-stabilization. Thus, this study proposes to understand the influence of the granular class of natural aggregates on the performance of laterites. To achieve this objective, different proportions of crushed granites of class 0/5, 0/15 and 5/15 have been incorporated into the soils of southern Côte d’Ivoire, especially in Samo. This modified soil has been subjected to mechanical tests such as the modified Proctor and CBR test. The results obtained show that the dry densities of the incorporated laterites containing crushed granites increase with the content of natural aggregates and decrease with the increase in the water content. Likewise, the CBR bearing indices at 95% of the Modified Optimum Proctor of the different compositions (laterites + crushed granites) increase with the proportion of aggregates. The addition of coarse aggregates to the laterites therefore promotes the establishment of a framework which improves its bearing capacity. From 20% to 30% crushed granites respectively of class 0/15;0/5 and 5/15, the values of the CBR obtained are greater than those of 30% therefore these modified soils can be used as a foundation layer for traffic of T1, T2 and T3 type. Likewise, the laterites’ mixtures with at least 40% crushed granites of class 0/15 and 0/5 can also be used for the foundation and base layers.展开更多
It had been suggested to use the West African Compaction Test Procedure since the early 1950’s so as to determine the CBR of gravel lateritic soils in West African countries [1]. This test procedure called West Afric...It had been suggested to use the West African Compaction Test Procedure since the early 1950’s so as to determine the CBR of gravel lateritic soils in West African countries [1]. This test procedure called West African Compaction (WAC) [2] is largely used in road construction in West African countries and had the particularity to be long and use a large amount of material. This note is the result of several comparisons between test procedures taken to determine the CBR from the WAC method to the standardized laboratory test commonly used to determine the CBR.展开更多
The presented study dealt with geotechnical investigations on the sub-grade soils along the connector road between the electrical transformer station and the industrial city, New Tiba city, Luxor, to classify these so...The presented study dealt with geotechnical investigations on the sub-grade soils along the connector road between the electrical transformer station and the industrial city, New Tiba city, Luxor, to classify these soils and to examine their geotechnical behavior and their proportionality for constructing the road at the study area. One of the most important aims of this work was to determine the problematic sub-grade soils and to recommend the suitable reclamation. To achieve these goals sixty disturbed samples from six mechanical wash drilling boreholes and three undisturbed samples from three open pits were collected. The studied soils were belonged to Quaternary age. Gradation parameters (coefficient of uniformity, Cu and coefficient of concavity, Cc), plasticity, California bearing ratio (CBR), proctor density and free swelling percent of the studied soils were measured. PH-value, dissolved chloride, dissolved sulfate, calcium carbonate, total carbonate, and total dissolved salts were determined. The results pointed that the studied Quaternary soils along the study road were mainly composed of gravels, sands and clayey sands. The studied gravels were classified as poorly graded gravels (GP) according to Unified Soil Classification System (USCS) and as A-1-b according to American Association of State Highway and Transportation Official (AASHTO). The studied sands were classified as well graded sands (SW) according to USCS and as A-1-a according to AASHTO. The results showed also that the sub-grades at boreholes no. 1, 3, 4, 5, and 6 were excellent to good and the sub-grade at boreholes no. 2 was fair to poor. Free swelling percent of the studied clayey sand soils was ranging from 30% to 80% and they were classified as low to medium grade expansive soil. Replacement and/or chemical stabilization (using lime and/or cement kiln dust) of the problematic clayey sands soils were suggested to reduce their swelling and to prevent the possible heave.展开更多
This study is carried out to appreciate the coarse elements influence of the gravel lateritic soils on the pavement behavior. The material involves not only the 0/20 mm granular particles considered in the specificati...This study is carried out to appreciate the coarse elements influence of the gravel lateritic soils on the pavement behavior. The material involves not only the 0/20 mm granular particles considered in the specifications and on the laboratory tests, but also all of the material that is actually used in the construction sites. Geotechnical characterization was leaned on five differentiated granular classes of 0/20;0/25;0/31.5;0/40 and 0/63 mm diameters. The sample of 0/40 mm gets the best compaction aptitude, while that of 0/31.5 mm reaches the greatest bearing strength and a good Optimum Moisture Content. According to the requirements and its bearing strengths, the material is usable up to subbase layer and its behavior depends on the grain size.展开更多
The ultrasonic pulse velocity(UPV)correlates significantly with the density and pore size of subgrade filling materials.This research conducts numerous Proctor and UPV tests to examine how moisture and rock content af...The ultrasonic pulse velocity(UPV)correlates significantly with the density and pore size of subgrade filling materials.This research conducts numerous Proctor and UPV tests to examine how moisture and rock content affect compaction quality.The study measures the changes in UPV across dry density and compaction characteristics.The compacted specimens exhibit distinct microstructures and mechanical properties along the dry and wet sides of the compaction curve,primarily influenced by internal water molecules.The maximum dry density exhibits a positive correlation with the rock content,while the optimal moisture content demonstrates an inverse relationship.As the rock content increases,the relative error of UPV measurement rises.The UPV follows a hump-shaped pattern with the initial moisture content.Three intelligent models are established to forecast dry density.The measure of UPV and PSO-BP-NN model quickly assesses compaction quality.展开更多
文摘This study explores an alternative to the classical use of direct methods, as water content and dry density measurements, for compaction quality control. For this purpose, the dielectric properties of lateritic materials are determined by radar method and are compared with the permittivity determined from the Topp formula and from the CRIM model. This approach allowed to establish a relationship between the geotechnical properties determined during compaction such as dry density, water content or porosity with dielectric permittivity. The obtained results made it possible to determine an optimum dielectric permittivity corresponding to the optimum dry density and the optimum water content that could be used for non-destructive in situ compaction testing. Such an approach should improve the implementation and effectiveness of in situ compaction quality control of geotechnical infrastructures.
文摘Background: COVID-19 limitations have hindered the implementation of new technologies by preventing proctors from coming to the site.We share our first experience of magnetic resonance imaging(MRI)-guided focused ultrasound(MRgFUS)treatment with an international remote online proctorship,and develop and evaluate the methodology of remote MRgFUS proctorship.Methods: This single-center,nonrandomized controlled prospective study included 94 patients:27 with essential tremor(ET)and 67 with tremor-dominant Parkinson's disease(PD).The coming of proctors was impossible,so we arranged for the remote participation of proctors from the United Kingdom,Spain,and Israel.A total of 38 patients(40.4%)received telemedicine-proctored treatment(proctor group)and 56 received their treatment independently(solo group).We used the Clinical Rating Scale for Tremor(CRST)for ET patients and the Unified Parkinson's Disease Rating Scale(UPDRS)Part III for PD patients.Results: In patients with ET,success rates were 81.8%(proctor group)and 100%(solo group)(p=0.22).CRST reduction on the treated side was 71.43%[65.83%;80.56%](proctor group)versus 60.87%[53.99;79.58](solo group)(p=0.19).None of the patients showed worsening of tremors within 1 year.In patients with PD,the success rates were 92.6%(proctor group)and 100%(solo group)(p=0.08).The UPDRS Part III improvement was 30.1%(proctor group)versus 39.9%(solo group)(p=0.003).The 1-year recurrence rate was 40%(proctor group)and 17.5%(solo group)(p=0.04).No complications were observed at 6 months.Conclusions: We developed a feasible and safe methodology for telemedicine remote online-proctored MRgFUS treatment.No significant difference was observed between the solo and developed remote proctor protocols in terms of complication rate,effect,and long-term results;however,UPDRS Part III improvement was better in the PD solo group.This study demonstrated that the MRgFUS international proctorship can be performed successfully remotely.
文摘Most of the laterites found in Ivory Coast do not meet the technical conditions to be used in their natural state for the design of road foundations. Also, to meet the growing needs for road materials, various amendments are made to them, including litho-stabilization. Thus, this study proposes to understand the influence of the granular class of natural aggregates on the performance of laterites. To achieve this objective, different proportions of crushed granites of class 0/5, 0/15 and 5/15 have been incorporated into the soils of southern Côte d’Ivoire, especially in Samo. This modified soil has been subjected to mechanical tests such as the modified Proctor and CBR test. The results obtained show that the dry densities of the incorporated laterites containing crushed granites increase with the content of natural aggregates and decrease with the increase in the water content. Likewise, the CBR bearing indices at 95% of the Modified Optimum Proctor of the different compositions (laterites + crushed granites) increase with the proportion of aggregates. The addition of coarse aggregates to the laterites therefore promotes the establishment of a framework which improves its bearing capacity. From 20% to 30% crushed granites respectively of class 0/15;0/5 and 5/15, the values of the CBR obtained are greater than those of 30% therefore these modified soils can be used as a foundation layer for traffic of T1, T2 and T3 type. Likewise, the laterites’ mixtures with at least 40% crushed granites of class 0/15 and 0/5 can also be used for the foundation and base layers.
文摘It had been suggested to use the West African Compaction Test Procedure since the early 1950’s so as to determine the CBR of gravel lateritic soils in West African countries [1]. This test procedure called West African Compaction (WAC) [2] is largely used in road construction in West African countries and had the particularity to be long and use a large amount of material. This note is the result of several comparisons between test procedures taken to determine the CBR from the WAC method to the standardized laboratory test commonly used to determine the CBR.
文摘The presented study dealt with geotechnical investigations on the sub-grade soils along the connector road between the electrical transformer station and the industrial city, New Tiba city, Luxor, to classify these soils and to examine their geotechnical behavior and their proportionality for constructing the road at the study area. One of the most important aims of this work was to determine the problematic sub-grade soils and to recommend the suitable reclamation. To achieve these goals sixty disturbed samples from six mechanical wash drilling boreholes and three undisturbed samples from three open pits were collected. The studied soils were belonged to Quaternary age. Gradation parameters (coefficient of uniformity, Cu and coefficient of concavity, Cc), plasticity, California bearing ratio (CBR), proctor density and free swelling percent of the studied soils were measured. PH-value, dissolved chloride, dissolved sulfate, calcium carbonate, total carbonate, and total dissolved salts were determined. The results pointed that the studied Quaternary soils along the study road were mainly composed of gravels, sands and clayey sands. The studied gravels were classified as poorly graded gravels (GP) according to Unified Soil Classification System (USCS) and as A-1-b according to American Association of State Highway and Transportation Official (AASHTO). The studied sands were classified as well graded sands (SW) according to USCS and as A-1-a according to AASHTO. The results showed also that the sub-grades at boreholes no. 1, 3, 4, 5, and 6 were excellent to good and the sub-grade at boreholes no. 2 was fair to poor. Free swelling percent of the studied clayey sand soils was ranging from 30% to 80% and they were classified as low to medium grade expansive soil. Replacement and/or chemical stabilization (using lime and/or cement kiln dust) of the problematic clayey sands soils were suggested to reduce their swelling and to prevent the possible heave.
文摘This study is carried out to appreciate the coarse elements influence of the gravel lateritic soils on the pavement behavior. The material involves not only the 0/20 mm granular particles considered in the specifications and on the laboratory tests, but also all of the material that is actually used in the construction sites. Geotechnical characterization was leaned on five differentiated granular classes of 0/20;0/25;0/31.5;0/40 and 0/63 mm diameters. The sample of 0/40 mm gets the best compaction aptitude, while that of 0/31.5 mm reaches the greatest bearing strength and a good Optimum Moisture Content. According to the requirements and its bearing strengths, the material is usable up to subbase layer and its behavior depends on the grain size.
基金supported by the National Natural Science Foundation of China (Grant Nos.52038005 and 52278342)Natural Science Foundation of Tianjin,China (Grant No.23JCJQJC00160).
文摘The ultrasonic pulse velocity(UPV)correlates significantly with the density and pore size of subgrade filling materials.This research conducts numerous Proctor and UPV tests to examine how moisture and rock content affect compaction quality.The study measures the changes in UPV across dry density and compaction characteristics.The compacted specimens exhibit distinct microstructures and mechanical properties along the dry and wet sides of the compaction curve,primarily influenced by internal water molecules.The maximum dry density exhibits a positive correlation with the rock content,while the optimal moisture content demonstrates an inverse relationship.As the rock content increases,the relative error of UPV measurement rises.The UPV follows a hump-shaped pattern with the initial moisture content.Three intelligent models are established to forecast dry density.The measure of UPV and PSO-BP-NN model quickly assesses compaction quality.
