What is the CENGRS Knowledge Center?

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. 

Book edited by our Director

Springer, a reputed international publisher of technical books, has published the book "Geotechnics for Transportation Infrastructure" edited by Ravi Sundaram, J.T. Shahu and V. Havanagi in two volumes.
The two volumes are a compilation of latest research and development on geotechnical aspects of design, construction, maintenance, monitoring and upgrading of roads, railways, metro-lines and other transportation infrastructure. 
Hopefully, the contribution by the various authors will lead to a better understanding of the subject, making this publication a valuable treatise on Transportation Geotechnics.

We have three interesting papers in the book covering various aspects of field geotechnical engineering.
See the links below:
Vol 1: https://www.springer.com/gp/book/9789811367007
Vol 2: https://www.springer.com/gp/book/9789811367120

Cengrs is commited to technical excellence and professionalism in geotechnical practice. The book is one step in that direction.

TECHNICAL PAPERS
Optimizing Foundation Design Through Quality Geotechnichnical Investigation – Case Study Of Bridge Across River Tapi
Ravi Sundaram, Sanjay Gupta, Sorabh Gupta, Rajesh Gupta, 01-Jan-2022

ABSTRACT: 

The quality of geotechnical data greatly influences the foundation design. Use of the right kind of equipment for geotechnical investigations can help in optimizing the foundation design and can result in substantial cost savings. The paper presents a case study illustrating the advantage that can be achieved by using triple tube core barrel to drill through weathered rock. Initial geotechnical investigations for a bridge across Tapi River carried out using “calyx” drilling rig and single tube core barrel yielded low core recoveries and RQD values. This resulted in a very conservative foundation design with bridge pier footings bearing at nearly 7 m depth into the basalt rock. To economize the design, a confirmatory geotechnical investigation was done at the same locations using a hydraulic core drilling rig with triple tube core barrel which confirmed high recovery and RQD values. Graphical plots of recovery and RQD with single and triple tube core barrel illustrate the substantial increase in these values when in the superior equipment is used. Although there is a lot of scatter in the data, it is evident that the use of triple tube core barrel gives a more realistic estimate of the core recovery and RQD values. As a result, the design is more economical and reliable. The design was revised based on the data which confirmed higher safe bearing pressures at shallower depths. The overall impact of the exercise was a direct saving of 1.86 crores in foundation cost alone (51% of the original estimate) based on a confirmatory investigation costing less than 15 lacs - a 1200% return on investment! In addition to this, there was indirect savings in cost of blasting, dewatering and manpower. The time saving was also substantial. 

Citation

Ravi Sundaram, Sanjay Gupta, Sorabh Gupta, Rajesh Gupta (2022), “Optimizing Foundation Design through Quality Geotechnical Investigation – Case Study of Bridge across River Tapi”, Journal of Indian Road Congress (IRC), [January-March, 2022], Volume 81-3, pp 46-53.

Quality Assurance of Large Diameter Base Grouted Bored Piles for a Railway Bridge in Bangladesh
Ravi Sundaram, Sorabh Gupta and Sanjay Gupta, 03-Jun-2022

Abstract 

Base-grouted piles of 1500 to 2500 mm diameter bored cast-in-situ piles were installed for a railway bridge over River Rupsa in Bangladesh. To ensure that the piles are safe to support the design loads, a comprehensive quality assurance program was implemented. This included conducting high-strain dynamic load tests and ultrasonic cross-hole sonic logging. The paper presents use of these tests to ensure that the piles are of acceptable quality and can support the loads safely. Typical results of selected tests are presented demonstrate the reliability of the tests conducted.

Citation 

Ravi Sundaram, Sorabh Gupta and Sanjay Gupta (2022), "Quality Assurance of Large Diameter Base Grouted Bored Piles for a Railway Bridge in Bangladesh", International Conference on Transportation Geotechnics GeoTrans-2022 1st to 3rd June, 2022.

Forensic Evaluation of Bored Piles For A Factory Project At Jhajjar
Ravi Sundaram, Sorabh Gupta and Sanjay Gupta, 01-Sep-2022

ABSTRACT 

A geotechnical forensic evaluation of piles for an industrial facility in Haryana was performed to assess the quality of the piles and to evaluate piles installed using two different types of rigs. Low strain pile integrity tests were performed on all piles to assess the pile length and possible presence of structural defects. Coring was done through questionable piles for the clinching evidence of concrete quality and pile length. Probe holes adjoining piles helped confirm the bulging of piles at shallow depth. The paper highlights the importance of implementing a well-planned quality assurance program to confirm that all piles installed are of the desired quality 

Citation 

Ravi Sundaram, Sorabh Gupta and Sanjay Gupta (2022), "Forensic Evaluation of Bored Piles For A Factory Project At Jhajjar", Proceeding DFI India-2022 Conference, Deep Foundations Institute of India at Tirupati on September 2022

Effect of Depth of Landfill on the Characteristics of Soil‑Like Material of Aged Waste: a Case study of Bhalswa dumpsite, India
Mohit Somani, Manoj Datta, G.V. Ramanna, Ingo Hölzle, Ravi Sundaram, and T.R. Sreekrishnan, 12-Aug-2022

Abstract 

In this study, an attempt has been made to characterize the municipal solid waste (MSW) accumulated for more than 25 years at Bhalswa dumpsite, New Delhi, India. Samples of MSW were collected in sampling tubes at a regular depth interval of 3 m up to a depth of 35 m from top and mid-height of the 65 m high dumpsite from boreholes drilled using percussion drilling. The variation of total unit weight, organic content, water content, and particle size distribution of the total MSW (collected inside the undisturbed sampling tube) with depth was assessed in order to understand the matrix of the waste mass accumulated inside the dump. Soil-like material (SLM, <4.75 mm) after screening total MSW through 4.75 mm sieve was also characterized for organic content and contaminants of concern (heavy metals (total as well as leachable), soluble salts, and release of dark-colored leachate). In total MSW, the total unit weight slightly increased with an increase in the depth of waste whereas organic content slightly decreased in the lower sections (25 to 35 m) of the boreholes. An increase in the percentage of soil-like material was observed with an increase in the depth of the waste. The total heavy metal concentration of Cr, Cu, and Zn in the SLM showed a significant increase (by an order of 50-80%) with an increase in the depth of waste. The leachable heavy metal concentration of Cr, Cu, and Ni in the SLM was also observed to significantly increase (20-50%) with an increase in the depth of waste. In the SLM, an increase in the soluble salts (by 10-15%) with an increase in the depth of waste was observed. The findings of this study can be useful for reclaiming dumpsites and suggesting possible valorization routes for excavated waste in developing countries like India. 

Citation 

Mohit Somani, Manoj Datta, G.V. Ramanna, Ingo Hölzle, Ravi Sundaram, and T.R. Sreekrishnan (2022), "Effect of depth of landfill on the characteristics of soil‑like material of aged waste: a case study of Bhalswa dumpsite, India", Journal of Material Cycles and Waste Management, © Springer Japan KK, part of Springer Nature 2022, https://doi.org/10.1007/s10163-022-01447-0, June 2022

Raft Foundation Analysis for a 135-m High-Rise Residential Tower in Noida
Ravi Sundaram, Sorabh Gupta, and Gyan Chand, 01-Dec-2022
Raft foundation for a 35-storeyed residential tower in Noida bearing on alluvial soils was analyzed using PLAXIS 3D software to assess the pressures and settlement at foundation level. To develop realistic geotechnical parameters to input into the finite element model, the borehole data was supplemented with in-situ pressuremeter tests and cross-hole shear tests. Using the updated soil parameters, the soil-structure interaction analysis justified the use of raft foundation without the need for piles.
Landslide at Govindghat - Investigation and Stabilization Measures
Ravi Sundaram, Sanjay Gupta, Minimol Korulla, Rudra Budhbhatti and Pankaj Mourya, 24-May-2021

Abstract. A cloudburst and flash flood in June 2013 in the state of Uttarakhand, India caused landslide at Govindghat located along a major highway. Large boulders in soil matrix were encountered in the area. Water seeping through the open pores between the boulders and erosion of the soil were the major causes of the slope-failure. Erosion of the accumulated debris on the valley side during periods of high discharge in the area also added to the instability. The stabilization measures adopted include a secured drapery of rock anchors and steel mesh on the hill side, nailed gabions at road level, reinforced soil wall to ensure the desired road width and river-side gabion wall for erosion protection.

Keywords: Landslide, Cloudburst, Boulder-soil Matrix, Seismic Refraction tests, Hill-slope Stabilization, Erosion Protection

Citation :  

Ravi Sundaram, Sanjay Gupta, Minimol Korulla, Rudra Budhbhatti and Pankaj Mourya (2021), “Landslide at Govindghat - Investigation and Stabilization Measures”, Proceedings, Fourth International Conference Transportation Geotechnics, 4ICTG, May, 2021, Chicago

Geotechnical and Geophysical Characterization – Case Study of a Site with Steeply Dipping Rock
Ravi Sundaram, Sorabh Gupta and Sanjay Gupta, 16-Dec-2021

Abstract. Geotechnical investigation at site for a multi-storeyed residential complex in south Delhi indicated the presence of steeply dipping and folded rock. The variation in the depth to rock within each tower highlighted the possibility of differential settlement of the raft foundation planned at basement level. To characterize the formation, seismic refraction tests were performed along four lines. The tests assisted in confirming the trend of the rock profile in the area of the towers. The geophysical evaluation was used to evaluate the dip of the rock clearly define the variation in the rock profile across the site.

Keywords: Geotechnical Investigation, Boreholes, Seismic Refraction Tests, Steeply Dipping Rock.

Citation :  

Ravi Sundaram, Sorabh Gupta & Sanjay Gupta (2021), “Geotechnical and Geophysical Characterization – Case Study of a Site with Steeply Dipping Rock”, Proceedings,  Indian Geotechnical Conference IGC-2021, December 16-18, 2021, NIT Tiruchuriappalli

Geotechnics of a Unique Irregular High-Rise Statue
Ravi Sundaram, Sanjay Gupta, Mohit Jhalani and Jitendra Kumar, 17-Dec-2020

Abstract.

Construction of a 107 m (351 ft) high Shiva statue on a hillock at Nathdwara, Rajasthan posed several challenges both geotechnical and structural. Detailed geotechnical investigation showed the presence of quartzite rock from the ground surface that is highly fractured at shallow depths and improves in quality with increasing depth. Rock anchors were provided for stability against wind and earthquake loading. The slopes in the surrounding areas were stabilized effectively by suitable measures. The structure details and other aspects of the elegant monument are described.

Citation :  

Ravi Sundaram, Abhay Gupta and Sanjay Gupta (2020), “Geotechnics of a Unique Irregular High-Rise Statue”, Proceedings, Indian Geotechnical Conference IGC-2020, December 17-19, 2020, Andhra University, Visakhapatnam.

Short Piles for a Solar Power Plant in Western Rajasthan
Ravi Sundaram, Abhay Gupta and Sanjay Gupta, 17-Dec-2020

Abstract:

Short bored cast-in-situ pileswere installed for a solar power plant in western Rajasthan. The deposits at site consist of dune sand underlain by rock. The paper discusses the load-displacement behavior of 350 mm diameter 2.65-2.8 m long piles under pullout and lateral loading. To evaluate ultimate pullout capacity of piles which were not tested to failure, a hyperbolic model of load-displacement curve has been proposed. The pullout test data has been used to back-calculate the value of earth pressure coefficient, k. The lateral pile capacity has also been analyzed to evaluate the value of modulus of horizontal subgrade reaction.

Citation:

Ravi Sundaram, Abhay Gupta and Sanjay Gupta (2020), “Geotechnics of a Unique Irregular High-Rise Statue”, Proceedings, Indian Geotechnical Conference IGC-2020, December 17-19, 2020, Andhra University, Visakhapatnam.

Geophysical Characterization of Metro Station Sites
Ravi Sundaram, Sanjay Gupta, Sorabh Gupta, 26-Jul-2019

Abstract

Seismic refraction tests are an effective tool to characterize the ground and correlate to the borehole profile and assess the trend of the rock formation. The paper presents case studies of the application of the tests to enhance the reliability of geotechnical data at metro station sites in Delhi. Data from three selected underground station sites are illustrated in detail.

Keywords—geophysical characterization, seismic refraction tests, metro station sites

Citation :

Ravi Sundaram, Sanjay Gupta, Sorabh Gupta (2019), “Geophysical Characterization of Metro Station Sites”,  International Conference on Geotechnics for High Speed Corridors 25th and 26th July 2019, Thiruvananthapuram, India

Failure of bored piles of a factory building – Forensic evaluation
Sanjay Gupta, Ravi Sundaram and Sorabh Gupta, 14-Oct-2019

Abstract

Excessive settlement was observed in piles installed for a factory building in Haryana. The paper presents results of forensic evaluation of two failed piles. Low strain pile integrity tests (PIT) and parallel seismic tests (PST) were used to effectively identify the defects. To physically confirm the defects, coring through the pile concrete was done.  The study effectively identified the nature of the defects and the depth at which the piles had major discontinuities.

Keywords: failed piles; forensic evaluation, pile integrity test; pile-concrete coring; parallel seismic test

Citation :

Sanjay Gupta, Ravi Sundaram and Sorabh Gupta (2019), “Failure of bored piles of a factory building – Forensic evaluation”, 16th Asian Regional Conference on Geotechnical Engineering, Taipei, Taiwan on 14th to 17th October, 2019

Stabilizing a Highway in the Fragile Himalayan Terrain – Case Study of Gulabkoti Landslide
Minimol Korulla, Ravi Sundaram and Sorabh Gupta, 14-Oct-2019

Abstract: 

The fragile Himalayan terrain of Uttarakhand (India) faces challenging and tough situations due to landslides, particularly during monsoons. A landslide triggered by a cloudburst resulted in rock-fall at Gulabkoti village, where highly jointed and fractured rocks were present. The paper discusses the destabilizing forces that triggered failure of the fragile hill-slopes. Investigations conducted and remedial measures proposed such as secured drapery system with anchors, retention with reinforced soil system in the valley side and drainage measures are discussed in detail.

Keywords: landslide; geotechnical investigation; rock-fall; water percolation; hill slope stabilization.

Citation :

Minimol Korulla, Ravi Sundaram and Sorabh Gupta and Meenu PS (2019), “Stabilizing a Highway in the Fragile Himalayan Terrain – Case Study of Gulabkoti Landslide”, 16th Asian Regional Conference on Geotechnical Engineering, Taipei, Taiwan on 14th to 17th October, 2019.

Predicting foundation behavior: In-situ tests for a multi-storeyed tower on alluvial sands
Ravi Sundaram, Sanjay Gupta and Sorabh Gupta, 14-Oct-2019

Abstract:

For design of heavily loaded foundations of tall multi-storeyed buildings and other structures, it has become imperative to make predictions of foundation settlement as close to the actual settlement as possible. Pressuremeter tests and footing load tests can help to validate the theoretical estimates and calibrate the design profile developed on the basis of a thorough geotechnical investigation. The paper presents analysis of the geotechnical investigation and footing load tests. Settlement predictions based on the geotechnical design profile has been compared to the actual values measured from the footing load test. Numerical simulation of the test conditions by finite element method to was used to validate the field results. The results of the field test are in good agreement with theoretical predictions, thus enhancing the reliability of foundation analysis.

Keywords: alluvial sands; geotechnical investigation; foundation behavior; pressuremeter test; footing load test; numerical simulation; validating predicted settlement

Citation :

Ravi Sundaram, Sanjay Gupta and Sorabh Gupta (2019), “Predicting foundation behavior: In-situ tests for a multi-storeyed tower on alluvial sands”, 16th Asian Regional Conference on Geotechnical Engineering, Taipei, Taiwan on 14th to 17th October, 2019.

Forensic Evaluation Of Defective Bored Piles Of An Industrial Plant
Sorabh Gupta, Ravi Sundaram and Sanjay Gupta, 15-Nov-2019

ABSTRACT

Settlement was observed in piles installed for an industrial facility in Haryana. The paper presents results of forensic evaluation of two piles. Low strain pile integrity tests (PIT) and parallel seismic tests (PST) were used to effectively identify the defects. To physically confirm the defects, coring through the pile concrete was done.  The study effectively identified the nature of the defects and the depth at which the piles had major discontinuities.

Keywords: defective piles, geotechnical forensic evaluation, pile integrity test, parallel seismic test, pile-concrete coring

Citation :

Sorabh Gupta, Ravi Sundaram and Sanjay Gupta (2019), “Forensic Evaluation Of Defective Bored Piles Of An Industrial Plant”, Proceeding DFI India-2019 Conference, Deep Foundations Institute of India at NAC Hyderabad on 15-16, November, 2019.

Strengthening of Equipment Foundations on Loose Soils of a Power Plant in Eastern Uttar Pradesh
Ravi Sundaram, Sanjay Gupta, Mohit Jhalani & Jitendra Kumar, 19-Dec-2019

Abstract. Small equipment foundations of a power plant placed on a 5-6-m thick poorly compacted fill underlain by rock experienced excessive settlements. Strengthening measures adopted included installing micro-piles extending to the top of rock and filling large voids in the fill with a thick grout of cement and sand. This highlights the importance of proper compaction as well as the need to test the bearing strata adequately before constructing foundations on fill.

Keywords: Excessive Settlement, Goeotechnical Investigations, Foundation Strengthening, Micro-piles, Cement-grouting.

Citation 

Ravi Sundaram, Sanjay Gupta, Mohit Jhalani & Jitendra Kumar  (2019), “Strengthening of Equipment Foundations on Loose Soils of a Power Plant in Eastern Uttar Pradesh”, Proceeding of the 11th International Conference on Geosynthetics (IGC-2019) on 19-21 December 2019, SVNIT Surat, Gujarat, India.  

ARTICLES
Recent Trend In Foundation Strengthening
Sanjay Gupta,Ravi Sundaram, 01-Oct-2017

Brief:Modern Foundation engineering can come to rescue of structures that have experienced signinficant foundation distress or failure.Detailed investigation of cause and mode of failure together with careful planning and sound engineering practice is the key to successful execution of the foundation strengthening process.Specific case histories of some projects in Delhi and Bihar are described explaining the nature of foundation distress and methodology adopted to stabilize the structures and ensuring adequate foundation Performance.

Pile Foundations Save Transmission Towers At Agra
Sanjay Gupta,Ravi Sundaram, 06-Sep-2017

Brief:The shifting of course of the Yamuna River at Agra by over 800 m during the last four years had threatened the stability of transmission towers of a 220 KV-tansmission line on the river bank.After last year's monsoons ,the river had shifted dangerously close to the existing towers.

Geotechnical Investigations - The Way Forward
Sanjay Gupta,Ravi Sundaram, 19-Sep-2017

Brief:A thorough geotechnical investigation is a pre-requisite for a reliable,safe and economical foundation design.It is important that whatever is envisaged at the investigation and design stage should translate into construction that is in sync with the design concepts,assumptions and predicted foundation behaviour.