Accelerated performance of a failed pavement on a soft clay subgrade after rehabilitation with high polymer mix at the NCAT pavement test track

2012 ◽  
pp. 203-207 ◽  
Author(s):  
R Powell
Keyword(s):  
Soft Clay ◽  
High Polymer ◽  
Test Track ◽  
Soft Clay Subgrade

scholarly journals An Improved Time-Series Model Considering Rheological Parameters for Surface Deformation Monitoring of Soft Clay Subgrade

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3073 ◽  
Author(s):  
Xing ◽  
Chen ◽  
Yuan ◽  
Shi
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Soft Clay ◽  
Deformation Monitoring ◽  
Rheological Parameters ◽  
Deformation Model ◽  
Rheological Parameter ◽  
Functional Relationships ◽  
Soft Clay Subgrade ◽  
Deformation Models

Building deformation models consistent with reality is a crucial step for time-series deformation monitoring. Most deformation models are empirical mathematical models, lacking consideration of the physical mechanisms of observed objects. In this study, we propose an improved time-series deformation model considering rheological parameters (viscosity and elasticity) based on the Kelvin model. The functional relationships between the rheological parameters and deformation along the Synthetic Aperture Radar ( SAR) line of sight are constructed, and a method for rheological parameter estimation is provided. To assess the feasibility and accuracy of the presented model, both simulated and real deformation data over a stretch of the Lungui highway (built on soft clay subgrade in Guangdong province, China) are investigated with TerraSAR-X satellite imagery. With the proposed deformation model, the unknown rheological parameters over all the high coherence points are obtained and the deformation time-series are generated. The high-pass (HP) deformation component and external leveling ground measurements are utilized to assess the modeling accuracy. The results show that the root mean square of the residual deformation is ±1.6 mm, whereas that of the ground leveling measurements is ±5.0 mm, indicating an improvement in the proposed model by 53%, and 34% compared to the pure linear velocity model. The results indicate the reliability of the presented model for the application of deformation monitoring of soft clay highways. The estimated rheological parameters can be provided as a reference index for the interpretation of long-term highway deformation and the stability control of subgrade construction engineering.

On the Construction Technology and Quality Control of Vacuum Combined Surcharge to Foundation Reinforcement

2014 ◽  
Vol 1030-1032 ◽  
pp. 827-829 ◽  
Author(s):  
Ze Jun Liu ◽  
Ya Guo ◽  
Qi Wang Yuan ◽  
Bao Hai Chen ◽  
Xiang Yang Gu ◽  
...  
Keyword(s):  
Soft Soil ◽  
Soft Clay ◽  
Engineering Application ◽  
Economic Benefits ◽  
Engineering Practice ◽  
Strengthening Effect ◽  
Construction Technology ◽  
Soil Consolidation ◽  
Vacuum Preloading ◽  
Soft Clay Subgrade

The vast area of distribution of soft clay with poor engineering property of our country, on the soft clay subgrade treatment by drainage consolidation method. As a kind of drainage consolidation method, vacuum preloading consolidation of soft soil foundation in recent years have been widely used, and achieved very good engineering and economic benefits. The theory research about vacuum preloading behind the engineering practice, restricted the further development of the technology and engineering application, it is necessary to make a systematic study. Through the comparative analysis of the test results, the vacuum causes soil consolidation, on this basis, the surcharge preloading and vacuum preloading contrast of the vacuum preloading mechanism, analyzes various factors foundation reinforcement finally strengthening effect by vacuum preloading.

scholarly journals Ground Subsidence Investigation in Fuoshan, China, Based on SBAS-InSAR Technology with TerraSAR-X Images

2019 ◽  
Vol 9 (10) ◽  
pp. 2038 ◽  
Author(s):  
Yikai Zhu ◽  
Xuemin Xing ◽  
Lifu Chen ◽  
Zhihui Yuan ◽  
Pingying Tang
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Soft Clay ◽  
Ground Surface ◽  
Ground Subsidence ◽  
Maintenance Cost ◽  
Deformation Model ◽  
Geotechnical Characteristics ◽  
Soft Clay Subgrade ◽  
Sbas Insar

Highways built on soft clay subgrade are more prone to subsidence due to the geotechnical characteristics of soft clay. Monitoring ground movements in this area is significant for understanding the deformation dynamics and reducing maintenance cost as well. In this paper, small baseline subset synthetic aperture radar interferometry (SBAS-InSAR) technique is exploited to obtain and investigate the time series ground surface deformation after the construction of a road embankment over soft clay settlement. Considering the important effect of temporal deformation models on the final accuracy of estimated deformation, both the linear velocity model and seasonal deformation model are utilized to conduct the comparative investigation of deformation time series. Two highways in Fuoshan, China—G1501 Guangzhou Belt Highway and Lungui Highway—were selected as the test area. Thirteen TerraSAR-X images acquired from October 2014 to November 2015 were analyzed. Comparative study based on two groups of analyses generated from the two models for both highways were conducted. Consequently, several feature points distributed near the two highways were analyzed in detail to understand the temporal evolution of the settlement. In order to evaluate the reliability of our measurements, the residual phase was analyzed to assess the modelling accuracy of the two models. In addition, leveling data were also used to validate the experimental results. Our measurements suggest that the seasonal model is more suitable for the test highways, with an accuracy of ±3 mm with respect to the leveling results.

scholarly journals INVESTIGATION ON INSAR TIME SERIES DEFORMATION MODEL CONSIDERING RHEOLOGICAL PARAMETERS FOR SOFT CLAY SUBGRADE MONITORING

2018 ◽  
Vol XLII-3 ◽  
pp. 1977-1982 ◽  
Author(s):  
X. Xing ◽  
Z. Yuan ◽  
L. F. Chen ◽  
X. Y. Yu ◽  
L. Xiao
Keyword(s):  
Time Series ◽  
Soft Clay ◽  
Stability Control ◽  
Deformation Monitoring ◽  
Rheological Parameters ◽  
Deformation Model ◽  
Unknown Parameters ◽  
New Model ◽  
Soft Clay Subgrade ◽  
Deformation Models

The stability control is one of the major technical difficulties in the field of highway subgrade construction engineering. Building deformation model is a crucial step for InSAR time series deformation monitoring. Most of the InSAR deformation models for deformation monitoring are pure empirical mathematical models, without considering the physical mechanism of the monitored object. In this study, we take rheology into consideration, inducing rheological parameters into traditional InSAR deformation models. To assess the feasibility and accuracy for our new model, both simulation and real deformation data over Lungui highway (a typical highway built on soft clay subgrade in Guangdong province, China) are investigated with TerraSAR-X satellite imagery. In order to solve the unknows of the non-linear rheological model, three algorithms: Gauss-Newton (GN), Levenberg-Marquarat (LM), and Genetic Algorithm (GA), are utilized and compared to estimate the unknown parameters. Considering both the calculation efficiency and accuracy, GA is chosen as the final choice for the new model in our case study. Preliminary real data experiment is conducted with use of 17 TerraSAR-X Stripmap images (with a 3-m resolution). With the new deformation model and GA aforementioned, the unknown rheological parameters over all the high coherence points are obtained and the LOS deformation (the low-pass component) sequences are generated.

THE CONSOLIDATION OF SOFT CLAY FOUNDATION GROUND USING GEOSYNTHETICS COMBINED WITH THE ELECTRO-OSMOSIS PROCESS

2020 ◽  
Author(s):  
Florin Sebastian Mustăţea ◽  
Raluca Ioana Nicolae
Keyword(s):  
Soft Clay ◽  
Electrical Current ◽  
Physical Models ◽  
Scale Model ◽  
Consolidation Process ◽  
Soft Clays ◽  
Electro Osmosis ◽  
Speed Up ◽  
Drainage Capacity ◽  
Soft Clay Subgrade

In the last decade, the construction of communication routes has intensified in Romania. As a result, many case studies related to the presence of saturated clayey soils in the foundation ground have emerged. In order to speed up the execution of highways and railways in a safely manner, the designers use different methods of improving soft clays in terms of compressibility. The present study aims to evaluate the efficiency of an electrical current used for the vertical dewatering of a soft clay subgrade, through simple physical models. The experimental study is being performed on a laboratory scale model by using electrodes and geosynthetics for drainage, along with the vacuum technique. The vertical drainage capacity during the electro-osmotic dewatering process, combined with preloading, drainage, vacuum and heat induction is being evaluated. The integrated effect of these methods on the consolidation process will be analyzed for the final conclusions.

Cost Comparisons of Remedial Methods to Correct Track Substructure Instability

2000 ◽  
Vol 1713 (1) ◽  
pp. 10-14 ◽  
Author(s):  
Steven Chrismer ◽  
David Davis
Keyword(s):  
Layer Thickness ◽  
Granular Layer ◽  
Soft Clay ◽  
Cost Effective ◽  
Wheel Load ◽  
Service Testing ◽  
Effective Selection ◽  
Track Substructure ◽  
Soft Clay Subgrade ◽  
Lower Material

The effectiveness and costs of various remedies for stabilizing track over a soft clay subgrade were tested and compared. To date, the techniques of repeated tamping, increasing granular layer thickness, and placing a geoweb layer have been tested under 39-kip (170-kN) wheel-load traffic. Using typical industry cost figures, economic analysis shows that the most cost-effective selection depends on traffic volume. For the heavy-axle load conditions studied at the Facility for Accelerated Service Testing (located at FRA’s Transportation Technology Center, Inc., near Pueblo, Colorado), analysis indicates that continued tamping of the ballast can be the best choice when the annual tonnage is less than about 40 million gross tons (MGT; 360 GN). For annual tonnage levels greater than 50 MGT (450 GN), fixing the problem by use of a remedial technique is less costly. Of the two remedies tested, increasing the granular layer thickness appears to be the lower cost option, mainly because of the lower material cost compared with geoweb. The intent of this analysis is to help railroads decide whether to make temporary repairs with low initial costs or more permanent remediation with higher initial costs.

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