At Cengrs, one of our core values is sharing of knowledge. Owing to our extensive experience in providing expert Geo-technical engineering services to the construction industry, we have over the years, gained significant knowledge about the key issues and challenges in this domain. To consolidate this valuable learning, we have established a Knowledge Centre, which primarily works on the theology of collating information & experiences, and disseminating it to interested organizations & individuals.

Through case studies and technical papers, our Knowledge Centre aims to serve as an excellent resource for anyone conducting Geo-technical activities. We strongly believe that this knowledge should be constantly refreshed and improved to provide companies with the required guidance & support for enhancing business processes and improving efficiency.

• 20-Oct-2015

  In-situ Testing to Verify Ground Improvement

  Mr. Ravi Sundaram & Mr. Sanjay Gupta

  Abstract: Reliability of improvement achieved is the key to the implementation of soil stabilization and ground improvement measures. In-situ tests are an essential part of the ground improvement process to confirm that the desired improvement in soil properties has been achieved. The paper presents two case studies in the Delhi-NCR area where ground improvement was done to mitigate liquefaction potential and improve the soil bearing capacity. In-situ tests conducted before and after improvement to verify the effectiveness of improvement include SPT (in boreholes), static cone penetration tests (SCPT) and plate load tests.

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• 18-Sep-2014

  Identifying Defects in Large Diameter Bored Piles Case Studies

  Ravi Sundaram & Sorabh Gupta

  Introduction : Construction of deep bored piles requires adequate quality assurance measures to ensure that the pile is free of major defects and can safely carry the design loads. The paper presents pile quality assurance tests implemented for two case studies of large diameter piles installed in the Indo-Gangetic Alluvium.

• 16-Jul-2014

  Building a University on Liquefiable Soils Using Dynamic Compaction

  Ravi Sundaram, Sanjay Gupta, Sorabh Gupta

  Abstract :A major University site spanning 511 acres with a total constructed area of 357 acres has recently been constructed in the state of Uttar Pradesh in north India. The campus, once established, shall boast of over 84,000 m2 of constructed area with 30 percent green cover. The site is located in the Yamuna flood plain, about 2 km. from the river.

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• 13-Sep-2012

  Article in Indian Infrastructure Magazine, Special Section:Foundation and Piling Works

  Sanjay Gupta et. al.

  Introduction :If the Twelfth Plan (2012-17) estimates of Over $1 trillion investment in infrastructure development fructify, it will present an enormous opportunity for the construction industry, and specifically for foundation and piling works. Construction is critical to infrastructure project development and, typically, 5 per cent or more of the cost of any civil engineering project in India is contributed by foundations and piling. The key market segments for foundation and piling works include roads and highways, power plants, marine structures, metro rail projcts, oil refineries, wate and stormwater drainage projects, airports, and comercial buildings and housing projects. \n\nThe Indian piling equipment market is estimated to be worth Rs.2 billion. The market has grown at a rate of about 20-25 per cent in the last few years, spurred by infrastructure development. However, the Indian market is still considered to be nascent and it is estimated that only about 200 piling-rela

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• 16-Aug-2012

  Quality Assurance for Deep Bored Piles A Case Study

  Sanjay Gupta, Ravi Sundaram, Sorabh Gupta

  Abstract : One of India’s tallest residential towers is being constructed in the state of Uttar Pradesh, not very far from the YamunaRiver. The development includes the construction of a 66-story residential tower rising about 240 meters above grade and having two basements extending about 9 meters below grade. The foundation system for the proposed development consists of a piled-raft system with a 2.5-meter thick reinforced raft, supported by 298 Nos. bored-cast-in-situ piles of 1 m diameter and 48 m depth. This paper describes the geotechnical investigations carried out at the project site to estimate the safe pile capacities, and presents the results of a rigorous quality assurance program executed by the authors to ensure foundation quality and performance in-situ.

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• 14-Aug-2012

  Building a Mega Power Plant on Liquefiable Sands- A Case Study

  Sanjay Gupta, Ravi Sundaram, Sorabh Gupta

  Abstract : Geotechnical investigation for a major power plant in Punjab indicated the likelihood of liquefaction of the loose sands to about 7.5-11 m depth. To mitigate the liquefaction potential, ground improvement by vibro-compaction was done for the light to medium loaded facilities. Piles extending well below the liquefiable zone were used to support heavily loaded facilities. The paper presents data and analysis for the Boiler-I area where ground improvement was done successfully done and raft foundation for the raft was provided.

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• 27-Oct-2011

  Liquefaction Risk Mitigation for a Power Plant in the Indo-Gangetic Alluvium

  Sanjay Gupta, Ravi Sundaram, Sorabh Gupta

  Abstract : The paper presents the case study of liquefaction studies for an upcoming power plant in the Indo-Gangetic plain. Geotechnical site characterization studies suggested that the sands to 8 m depth were prone to liquefaction during the design earthquake. Accordingly, TG, chimney and other heavily-loaded facilities were supported on piles extending well below the liquefiable zone. Ground improvement by vibro-replacement was done in other areas of the site to mitigate the liquefaction potential.

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• 22-Oct-2011

  Geotechnical Characterization Of Soft Clays Of The Godavari Delta

  Sanjay Gupta, Ravi Sundaram, Sorabh Gupta

  Abstract : Soft under-consolidated clay is encountered to substantial depth in the Godavari Delta of coastal Andhra Pradesh. Constructing foundations in such weak deposits needs careful assessment of the geotechnical properties. This paper presents details of geotechnical investigations carried out for an onshore gas terminal project in such strata, an evaluation of the ground improvement methods employed at the site, and details of the selection and testing of the foundation system adopted for statically and dynamically-loaded facilities.

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• 02-Nov-2010

  Constructing Foundations On Red Mud

  Ravi Sundaram & Sanjay Gupta

  Abstract: \nFor the expansion of an Aluminium plant in eastern Uttar Pradesh (India), it was required to construct an industrial facility on a slurry pond formed by pumping Red Mud, the waste product of the processing of aluminium ore. Since the Red Mud deposition behaves as a soft clay, ground improvement was done by provision of granular piles / rammed stone columns. The granular piles were load tested to verify the efficacy of the improvement

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• 11-Oct-2010

  Dynamic Compaction to Mitigate Liquefaction Potential

  Sanjay Gupta, Ravi Sundaram & Sorabh Gupta

  Abstract: At a project site in Greater Noida (U.P.), loose to medium dense ‘clean’ Yamuna sands were encountered, which were found to be susceptible to liquefaction to about 8-12 m depth. Dynamic compaction was carried out across the entire site to densify the soils and mitigate the risk of liquefaction. Field tests (including standard penetration tests and static cone penetration tests) carried out before and after dynamic compaction indicated that the ground improvement has been successful to the desired depth. Open foundations bearing on the improved ground could now be provided in place of piles, resulting in enormous cost-saving for the owner.

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• 02-Sep-2009

  Performance of a Large Diameter Oil Storage Tank on Improved Clay Deposit

  Gopal Ranjan, Ravi Sundaram and Sanjay Gupta

  Abstract:Large diameter cylindrical welded steel tanks bearing on soft clay deposits can experience substantial settlement. Ground improvement by provision of granular piles is an effective method to strengthen the soft clay and control settlements within acceptable limits. The paper presents the installation technique together with results of load tests conducted on trial granular piles to assess the behavior of the improved ground. The tank performance, evaluated by hydro-testing the tank, compared well with the theoretical model used to compute the settlement of the improved ground

• 02-Nov-2008

  Pile Integrity Testing for Monitoring Pile Construction

  Sanjay Gupta, Ravi Sundaram and Sorabh Gupta

  Abstract: Low-strain Pile Integrity Testing (PIT) is a valuable, low-cost tool to locate major defects in, and estimate pile lengths of, bored and driven piles installed on site. It can serve to enhance the confidence level of the engineer on the quality of piles installed. The paper discusses the test procedure and limitations, and illustrates field results of low strain integrity tests performed on RCC bored cast-in-situ piles on infrastructure projects.\n

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• 04-Sep-2008

  Pump-out Tests in Alluvial Sands-A Case Study

  Sorabh Gupta, Sanjay Gupta and Ravi Sundaram

  Abstract: For design of the dewatering system for construction of a multi-storeyed building with three basements, pump-out tests were conducted to evaluate the various hydraulic parameters of the aquifer. The deposits at site consist of fine sands of alluvial origin. The test results indicated very high permeability of the aquifer, necessitating a complex dewatering system that was not envisaged earlier. The paper presents details of the test conducted and analysis of the test results.

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• 03-Sep-2008

  Liquefaction Susceptibility Study at Commonwealth Games Village Delhi

  Sanjay Gupta, Ravi Sundaram, Sorabh Gupta and G.V. Ramana G.V. Ramana Department of Civil Engineering, Indian Institute of Technology, Delhi

  Abstract: Geotechnical investigations were carried out at the site of the Commonwealth Games-2010 Village site near Akshardham in New Delhi. The study included Spectral analysis of Surface Waves (SASW) tests conducted in conjunction with boreholes and static cone penetration tests to assess the liquefaction susceptibility during earthquakes. Detailed liquefaction susceptibility studies confirmed that soils to a depth of about 9.5 m are susceptible to liquefaction hazard. The paper discusses the approach used for the analysis together with the foundation system adopted.

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• 03-Sep-2007

  Geotechnical Characterization of Dune Sands of the Thar Desert

  Sanjay Gupta and Ravi Sundaram

  Abstract: The aeolian sands of the Thar Desert are meta-stable in nature and experience volume change on contact with water even without application of load. The construction of a major power plant with heavily loaded statically and dynamically loaded facilities on such deposits requires a thorough appreciation of the engineering behavior of dune sands. The paper documents the detailed geotechnical investigations conducted for the project. Highlights of the results include -\n\n(i) the poorly graded sands have predominantly one particle size, \n(ii) SPT values are influenced by the overburden pressure, \n(iii) the dry sands have high electrical resistivity \n(iv) settlement increase of open foundations upon saturation is nearly 2.8 times, and \n(v) poor dynamic response of the collapsible sands is observed at shallow depths with two peak

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• 02-Nov-2006

  Dynamic Characteristics of Alluvial Deposits-A case Study

  Sanjay Gupta, Ravi Sundaram and Anurag Goyal

  Abstract: The dynamic behavior of alluvial deposits of the Indo-Gangetic Alluvium depends primarily on the soil type, density and compactness. The paper presents results of cross-hole seismic tests and seismic refraction tests conducted at a power plant site in Haryana. The borehole and static cone penetration test data have been correlated to the P-wave and S-wave velocities to generate a geophysical model of the site conditions. From the test results, a four-layer model has been established for the project site.\n

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• 05-Sep-2005

  Deep Excavation Adjacent to a Multi-Storeyed Building Lateral Support

  Sanjay Gupta, Ravi Sundaram and Pushpendra Singh

  Abstract: To ensure safety of a tall multi-storeyed building adjacent to a deep excavation, cement grouting was done. The paper explains the site conditions and the scheme adopted. The grouting assisted in restraining lateral soil movement. Field observations confirmed that no soil movement occurred till the time the basement wall was constructed up to ground level.

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• 04-Sep-2005

  Mitigating Foundation Distress

  Sanjay Gupta and Ravi Sundaram

  Abstract: Mitigation of foundation distress deals with the science and art of saving foundations from distress or failure. Foundation distress refers to serviceability failure or may cause failure during the life of the structure. The approach for mitigating foundation distress is similar to that of Forensic Geotechnical Engineering, without involving court of law. Evaluation of what went wrong and why (the 4W’s) is the key to solve the problem and develop appropriate foundation rehabilitation system. The paper presents three case studies demonstrating the approach. In the cases presented, the ultimate failure had not taken place but distress in foundation had affected serviceability criteria and/or resulted in reduction in desired factor of safety. \n

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• 08-Nov-2004

  Geotechnical Investigations: Dune Sands of the Thar Desert

  Sanjay Gupta & Ravi Sundaram

  Synopsis: The aeolian sands of the Thar Desert are meta-stable in nature and experience volume change on contact with water even without application of load. Geotechnical investigations for a major power plant with heavily loaded statically and dynamically loaded facilities on such deposits requires a thorough appreciation of the engineering behavior of dune sands. The paper documents the detailed geotechnical investigations conducted for the project. Highlights of the results include (i) the poorly graded sands have predominantly one particle size, (ii) SPT values are influenced by the overburden pressure, (iii) the dry sands have high electrical resistivity (iv) settlement increase of open foundations upon saturation is nearly 2.8 times.

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• 21-Nov-2003

  In-situ Testing Current Trends in Geotechnical Investigations

  Sanjay Gupta and Ravi Sundaram

  Abstract: The new emerging trend in modern geotechnical investigation is to place a greater emphasis on in-situ tests. These tests can be effectively used to predict foundation behaviour with a higher factor of reliability. The paper presents four different types of advanced in-situ testing techniques with three case histories to demonstrate effective use of such advanced in-situ tests – static cone penetration tests, pressuremeter tests, geophysical tests.\n

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