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
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.  

Seasonal Variations in Properties of Expansive Soils along a Railway Corridor in Western India
Sanjay Gupta, Ravi Sundaram and Sorabh Gupta, 07-Apr-2018

ABSTRACT:

The properties of expansive soils at shallow depth are influenced by moisture variations due to seepage of water into the soils during rains. The paper presents a case study in western India along a railway freight corridor. Testing on samples collected from boreholes drilled in the pre-monsoon and post-monsoon periods indicate substantial variations in moisture content, undrained shear strength and swell pressure to about 3-3.5 m depth. Below this depth, these properties show insignificant change. This confirms that the active zone, the geotechnically unstable zone in expansive soils that undergoes swelling-shrinkage due to moisture variations extends to about 3.5 m depth.

Citation : Sanjay Gupta, Ravi Sundaram & Sorabh Gupta (2018), “Seasonal Variations in Properties of Expansive Soils along a Railway Corridor in Western India”, Proceedings, International Symposium on Geotechnics for Transportation Infrastructure (ISGTI-2018), New Delhi, India.

Geotechnical Evaluation of a Landslide in the Lesser Himalayas
Ravi Sundaram, Sorabh Gupta, Rudra Budhbhatti & Kinjal Parmar, 07-Apr-2018

ABSTRACT:

A landslide at Birahi in Chamoli District of the Lesser Himalayas had affected traffic along NH-58. The paper presents details of the geotechnical and geophysical investigations done to evaluate the failure and to develop remedial measures. A slide-zone of overburden with boulders was clearly identified which matches well with the borehole data. The probable causes of failure and remedial measures such as drainage planning, erosion control and reinforcement on valley side are discussed.

Citation : Ravi Sundaram, Sorabh Gupta, Rudra Budhbhatti & Kinjal Parmar (2018), Geotechnical Evaluation of a Landslide in the Lesser Himalayas, Proceedings, International Symposium on Geotechnics for Transportation Infrastructure (ISGTI-2018), New Delhi, India .

Geotechnical Design Parameters for a Metro Tunnel from Pressuremeter Tests
Ravi Sundaram, Sanjay Gupta, Sorabh Gupta & Bhajan Lal, 07-Apr-2018

ABSTRACT:

Being an in-situ test, the pressuremeter provides a reliable assessment of soil parameters, eliminating the influence of sample disturbance. The paper outlines analysis of pressuremeter data to interpret parameters such as undrained shear strength, pre-consolidation pressure, over-consolidation ratio and in-situ horizontal stress. The test was used effectively in conjunction with borehole data to assess the geotechnical parameters for design of a metro tunnel. Data from two locations along the metro tunnel alignment are presented here.

Citation : Ravi Sundaram, Sanjay Gupta, Sorabh Gupta & Bhajan Lal (2018), Geotechnical Design Parameters for a Metro Tunnel from Pressuremeter Tests”, Proceedings, International Symposium on Geotechnics for Transportation Infrastructure (ISGTI-2018), New Delhi, India

Bidirectional Static Load Test – Case Studies
Justin St. George, Ravi Sundaram, Sorabh Gupta, 15-Nov-2018

Abstract

Bi-Directional Static Load Pile Tests (BDSLT) was performed on a barrette pile of dimensions 1.2 m x 2.8 m extending to 21.278 m below the cut-off level. The test load applied was 10,800 tonnes which can usually not be applied by a traditional static load test. The test results indicated that the pile mobilized an ultimate unit skin friction value of 188.4 T/m2 and an end bearing result of 734.5 T/m2. Equivalent load-settlement curve indicates settlement of 4.6 mm at 100% the proposed working load, and 7.8 mm for 150% of the working load.

Keywords: Ultimate Load Test, Working Load Test, Bi-Directional Static Load Test, Skin Friction, End Bearing, Kentledge Test

Citation:

Justin St. George, Ravi Sundaram, Sorabh Gupta (2018), “Bidirectional Static Load Test – Case Studies”, Proceeding DFI India-2018 Conference, Deep Foundations Institute of India, Gandhinagar

Assessing Depth of Well Foundation – Case Study
Ravi Sundaram, Sanjay Gupta, Sorabh Gupta, 17-Nov-2018

Abstract

Parallel seismic test and sonic pulse echo response test are effective non-destructive methods to determine the depth of an existing foundation. The paper presents a case where depth of well foundation installed for a bridge across a drain was questioned by the owner. While the contractor insisted that the well depth was 12.2 m below the well cap as per the drawings, the owner doubted it. The tests provided a scientific basis for confirming the as-constructed depth of the foundation.

Keywords: foundation depth assessment, NDT Testing, Parallel seismic test, sonic echo response test, well foundations

 

Citation:

Ravi Sundaram, Sanjay Gupta, Sorabh Gupta (2018), “Assessing Depth of Well Foundation – Case Study”, Proceeding DFI India-2018 Conference, Deep Foundations Institute of India, Gandhinagar.

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.