A field investigation was conducted with four intelligent compaction/continuous compaction control rollers to characterize the spatial reporting of vibratory roller-measured soil properties and to investigate global positioning system (GPS)-based position reporting error. The key reporting characteristics examined include the spatial resolution of roller measurement values (MVs) and the volume/area reflected in each MV. Each vibration-based roller MV investigated is a reflection of soil properties over spatial dimensions that vary across manufacturers. The reporting resolution of roller MVs also varied across manufacturers. Three sources of GPS-determined position error were observed, namely, (1) accuracy of GPS, (2) unaccounted for physical offset of roller-mounted GPS receiver from the drum center, and (3) the spatial averaging of vibration data during roller MV calculation coupled with possible computational latency. The physical offset error was found to be as great as 1.0-2.0 m, while the error due to spatial averaging of vibration data coupled with latency ranged from 0.4 to 0.8 m. Both of these errors are significant but can be estimated and corrected by using a validation procedure described in the paper. Left uncorrected, these errors have a significant adverse effect on the analysis and interpretation of roller MV data when used in quality control/quality assurance specifications.

TRB's National Cooperative Highway Research Program (NCHRP) Report 676: Intelligent Soil Compaction Systems explores intelligent compaction, a new method of achieving and documenting compaction requirements. Intelligent compaction uses continuous compaction-roller vibration monitoring to assess mechanistic soil properties, continuous modification/adaptation of roller vibration amplitude and frequency to ensure optimum compaction, and full-time monitoring by an integrated global positioning system to provide a complete GPS-based record of the compacted area--

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Frontiers in Civil and Hydraulic Engineering focuses on the research of architecture and hydraulic engineering in civil engineering. The proceedings feature the most cutting-edge research directions and achievements related to civil and hydraulic engineering. Subjects in the proceedings including: Engineering Structure Intelligent Building Structural Seismic Resistance Monitoring and Testing Hydraulic Engineering Engineering Facility The works of this proceedings can promote development of civil and hydraulic engineering, resource sharing, flexibility and high efficiency. Thereby, promote scientific information interchange between scholars from the top universities, research centers and high-tech enterprises working all around the world.

The successful implementation of intelligent compaction technology into earthwork construction practice requires knowledge of the roller-integrated compaction measurements and their relationships with the engineering and index properties of soil that may be used for pavement design (e.g. California bearing ratio, elastic modulus, resilient modulus). These relationships were studied at three earthwork construction projects in Minnesota. In these field studies, intelligent compaction and in-situ test data were collected to demonstrate use of the various technologies, characterize the variation associated with each measurement system, and ultimately aid performance of regression analyses. For the pilot study at TH 64, a GIS database was created with roller data and parallel quality assurance data to demonstrate one method for managing large quantities of data. Spatial statistics were also determined using variogram modeling and discussed with regards to their potential for characterizing uniformity. A laboratory compaction study using different compaction methods (e.g. static, impact, gyratory, and vibratory) was conducted to show different moisture-density-compaction energy relationships for granular and cohesive soils. Resilient modulus test results showed that vibratory and impact compaction methods produce higher-modulus samples than static compaction. The findings from field studies of intelligent compaction systems provide the basis for developing QC/QA guidelines regarding effective and appropriate use of the technology. These recommendations, along with a brief summary of European specifications for continuous compaction control, are provided in the report.

This report describes a study of intelligent compaction (IC) technologies, within the context of actual construction projects, for its potential as a component of INDOT's QC/QA for soils. The output from an IC-equipped roller compaction equipment is a real-time area mapping of the compacted lift stiffness as captured by the IC measure. Data was collected to evaluate the correlation between each of two IC measures-compaction meter value (CMV) and machine drive power (MDP)-and in situ embankment quality test measures, the chief in situ test being the dynamic cone penetrometer (DCP) test which INDOT uses for soil embankment acceptance testing. Researchers sought to understand how well the IC measures might assess embankment quality as currently evaluated by the in situ measures. Window-averaged IC measures were compared with the in situ DCP test points. For CMV, a variable correlation was found between the average CMV and DCP values from 74 in situ locations. Also, a limited head-to-head comparison of CMV and MDP with the in situ measures provided some indication that MDP should be studied further. Lessons were learned regarding the elimination of bias in future correlation studies, critical provisions to facilitate best data quality, and important aspects of data management. IC technology holds promise for monitoring the consistency of the soil compaction effort and flagging weak areas in real time during compaction operations. However, further insight is needed regarding the correlation of the DCP measure with both types of IC measures for various soil characterizations and field moisture conditions.

When constructing earthen embankments, it is essential that the soil be placed and spread in uniform lifts prior to compaction. To ensure that the resulting soil lifts are evenly compacted, typical compaction specification approaches place restrictions on the thickness that is acceptable for each soil lift. In current practice, it can be extremely difficult for a field inspector to verify that lift thickness requirements are being met when soil is being placed and spread over a large area, without the use of frequent surveying (which adds both costs and delays to earthwork projects). Recent advances in compaction control include the development of continuous compaction control (CCC) and intelligent compaction (IC) systems, which provide real-time monitoring and feedback about the operation and performance of soil compaction. Typically, CCC and IC compaction equipment is outfitted with a real-time kinematic global positioning system (RTK-GPS) that monitors and records the position of the compacter as the soil lift is being compacted. This paper suggests that geotechnical engineers use field RTK-GPS measurements that are made by CCC or IC equipment to monitor and control the thickness of compacted soil lifts. Data collected from a full-scale field study is used to illustrate the practical issues with using GPS measurements for field monitoring of lift thickness during construction of a roadway embankment, such as varying roller position from lift-to-lift and the measurement uncertainty associated with RTK-GPS measurement data. The use of both simple and sophisticated spatial analysis techniques are explored for interpolating measured field elevation data onto a uniform grid for lift thickness assessment. The resulting methodology that is presented can be utilized to build spatial maps of compacted soil lift thickness, a process that can be used to great benefit by field engineers who are trying to ensure the quality of compacted soil lifts.