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 technicl 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 

Video Presentations

Mr. Ravi Sundaram delivered a Webinar Lecture titled "Geotechnical Investigations in Difficult Ground Conditions - Field Experiences" on 18th June 2020. The lecture was organized by the Indian Geotechnical Society Guntur Chapter through its Students Chapter at the Malineni  Perumalu Educational Society's group of institutions. Attended by over 150 persoms from all over India, the lecture was very well received by the geotechnical fraternity.

In his lecture, Mr. Ravi Sundaram emphasized on the need for thorough geotechnical investigations and use of advanced testing technologies to overcome complex geotechnical challenges. He presented three case studies as given below:

  1. Soft Clays in Kochi, Kerala
  2. Boulder -gravel deposits in foothills of the Himalayas
  3. Artesian conditions in the terai regions of the Indo-Nepal border.

You may watch the lecture by clicking on the following link:

https://youtu.be/ws3zGRsmsNo

TECHNICAL PAPERS
Geotechnics of Artesian Flow Case Study of River Shivganga, Nepal
Sanjay Gupta & Ravi Sundaram, 03-Oct-2003

Abstract: Geotechnical investigations done for the bridge across River Shivganga on the Kohalpur-Mahakali Highway in the Terai region of southwestern Nepal reveal the occurrence of multiple layers at different depths with artesian ground water flow. The concept for foundation design in such strata should consider three aspects – (a) bed boiling (quick condition) should not develop even if maximum scour occurs, (b) during construction, a minimum soil cushion thickness should be available between foundation level and strata with artesian flow, and (c) for long term stability, the bearing capacity at artesian level should be computed using effective stress principle. The application of these concepts to fix the founding levels for well foundations for the bridge is discussed

Citation :  Ravi Sundaram and Sanjay Gupta (2003), Geotechnics of Artesian Flow – Case Study of River Shivganga, Nepal, Proceedings, 12th Asian Regional Conference on Soil Mechanics & Geotechnical Engineering (12th ARC-2003), Singapore, Volume-I, pp 603-606.

Foundation Stabilization of the Janmabhoomi Temple at Mangarh
Ravi Sundaram and Sanjay Gupta, 05-Sep-2003

Synopsis: The Janmabhoomi Temple is planned as an elegant structure in granite stone blocks. The foundation block bearing at 3 m depth is a 5.4 m thick massive platform made of granite masonry. Review of the soil condition revealed that under the design loads, the total and differential settlement may be excessive. To stabilize the foundation system, confinement of the foundation block was done by providing a row of 400 mm diameter closely spaced piles all around the Garba Griha, and in the central Mandap portion. Ground improvement was done in the associated structures (small temples corridor) to strengthen the soils and to restrict settlement.

Citation : Ravi Sundaram and Sanjay Gupta (2003), Foundation Stabilization of the Janmabhoomi Temple at Mangarh, Proceedings, Forensic Geotechnical Engineering Chennai, pp 168-172.

Dynamic Properties of Delhi Silt from Field Investigations
H. Rao, S.Gupta, S. Narasaiah and G.V. Ramana (2002), 25-Jun-2002

Abstract:

All the earthquake resistant design and analysis procedures require site-specific/local dynamic site characterization. Dynamic site characterization includes shear wave velocity profile with depth, modulus reduction curves and damping characteristics of local soils. These are very essential and basic parameters required to conduct local site response/seismic wave propagation studies that should be duly incorporated into any earthquake resistant deign/analysis.

Shear wave velocity profiling is not a routine geotechnical investigation activity, as very specialized methods like seismic reflection, refraction, seismic cross-hole, down-hole and steady state vibration tests which fall under the domain of geophysical methods, are required which are very time consuming and expensive. A rapid, inexpensive method of finding shear wave velocity profile at a site is Spectral Analysis of Surface Wave (SASW) method.

Correlating Borehole Data with Electrical Resistivity Test Results
Ravi Sundaram and Sanjay Gupta, 11-Jan-2001

Introduction:On major projects, the geotechnical investigation activity usually involves a variety of different tests. To check the consistency of the results, it is essential that the data from different tests are comparable and lead to similar conclusions. This may be done by theoretical or empirical correlations that should be checked and calibrated using actual field data.

The paper will present the field application of a simple correlation that helps to interpret the litholog from the electrical resistivity test. The interpretation is compared to the actual borehole data. Such a comparison can also be used as a quality check on the resistivity data.

Data from two project sites will be presented. The first project relates to geotechnical investigation for a Captive Power Plant at Raipur (Chattisgarh) and the second one is for a 500 MW Coal based power project at Samalkot (Andhra Pradesh).

Citation : Ravi Sundaram and Sanjay Gupta (2001), Correlating Borehole Data with Electrical Resistivity Test Results, Proceedings, Indian Geotechnical Conference (IGC-2001), Indore, pp 44-47.

Risk in Estimation of Ultimate Loads of Ash Fill By Model Tests
Anurag Goyal, V.K. Sood, 13-Jan-2001

SYNOPSIS : The paper presents reliability of bearing capacity equations for calculating ultimate load with respect to Model Plate Load Test o ash fill at different depths. The advantage of conducting Model Tests is that the test parameters that influence the estimated value of ultimate load significantly can be controlled effectively. As there is serious problem of disposal of fly ash, this study is done on compacted ash fill with a view to use it in land filling and reclamation of low lying areas. For this, an experimental program has been conducted to study the difference in the measured ultimate load by Model Plate Load Tests (MPLT) and bearing capacity equitation. The result indicate that the bearing capacity equation over-estimates the actual value of bearing capacity for D/B ratio <0.5 and under-estimates the bearing capacity value for D/B ratio >1.0.

Citation :  Anurag Goyal and V.K. Sood (2001), Risk on Estimation of Ultimate Loads of Fly-ash Fill by Model Tests, Proceedings, Indian Geotechnical Conference (IGC-2001), Indore, pp 175-177.

Behavior of Dune Sands of the Thar Desert Under Dynamic Loading
Sanjay Gupta and Ravi Sundaram, 23-Feb-2001

Abstract: Forced vibration test were conducted on concrete blocks for a power project in north-western Rajasthan (India). The site is in the Thar desert and has meta-stable aeolian sand deposits. At shallow depth, the amplitude versus frequency curves shows two peaks, suggesting that the soil structure was probably collapsing and settling under the dynamic load. Tests conducted on the deeper, relatively more stable soils confirm a good response to dynamic loads. The instability under static loading conditions is also highlighted and correlated to the dune morphology.

Citation :  Sanjay Gupta and Ravi Sundaram (2001), Behavior of Dune Sands of the Thar Desert Under Dynamic Loading, Proceedings, Fourth International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics including Symposium in Honour of Professor W.D. Liam Finn, San Diego, California (USA), Volume II.

Use of Electrical Resistivity Tests for Geotechnical Investigations for Bridges
Ravi Sundaram & Sanjay Gupta, 03-Sep-2001

Background Inforamtion : The Ministry of Surface Transport (MOST) specifications for major bridges states that geotechnical investigation must done at every pier and abutment location. The normal practice is to drill boreholes at every location to a depth of “1.5 to 2B” (where B = foundation width) below founding level. This is sometimes supplemented by static cone penetration tests.

The paper presents the use of electrical resistivity test as an investigation tool to supplement the borehole data. The technique is time saving and is particularly useful in the current scenario of fast track projects in the highways and infrastructure sector.

Used in conjunction with boreholes, the electrical resistivity test can confirm continuity of the various strata and the depth of the layers. In strata containing boulders and rock formation in which drilling is time consuming and expensive, substantial savings in cost and time can be achieved by judicious inclusion of electrical resistivity tests in the geotechnical investigation programme.

Citation : Ravi Sundaram and Sanjay Gupta (2001), Use of Electrical Resistivity Tests for Geotechnical Investigation for Bridges, Journal of the Indian Roads Congress, Paper No.473, Volume 62(1), pp 115-131.

Implementation of Highway : Geotechnical Aspects
Sanjay Gupta, Ravi Sundaram, 21-Apr-2000

Synopsis: The metropolitan cities are facing problems of traffic and transportation (Gopal Ranjan 1996). Site investigation is the first crucial step in the design and construction of highways. A carefully planned and properly executed investigation can result in a greater degree of confidence in the design and realistic evaluation of highway performance in addition to cost effectiveness.

Citation : Sanjay Gupta and Ravi Sundaram (2000), Implementation of Highway Projects : Geotechnical Aspects”, Proceedings, Seminar on Financing, Implementation and Operation of Highways in 21st Century, Indian Roads Congress, New Delhi, pp III-157-161.

Ensuring Modern Reliability Of Foundation Design Rough Geotechnical Investigation Techniques
Ravi Sundaram, Sanjay Gupta, 05-May-2000

Synopsis: Geotechnical engineering provides the vital input for design of foundations which is of paramount importance for reliability in the performance of civil engineering structures. The paper presents a discussion on how modern field investigation techniques and in-situ testing backed up by a through laboratory testing programme can revolutionize foundation design. A carefully planned and properly executed investigation can results in a greater degree of confidence in the design in addition to cost effectiveness.

Citation: Ravi Sundaram and Sanjay Gupta (2000), Ensuring Reliability of Foundation Design Through Modern Geotechnical Investigation Techniques, Proceedings QUARS 2000, National Seminar on Quality Assurance and Reliability in Structures, Association of Consulting Civil Engineers (India), Coimbatore Centre.

Geotechnical Design Criteria for Foundations of Large Diameter Tanks
Gopal Ranjan, Ravi Sundaram and Sanjay Gupta, 23-Feb-2000

Synopsis: Large diameter steel tanks are commonly used to store large volumes of crude oil,petroleum etc.The paper reviews the geotechnical design criteria for the foundation system for such tanks.where tanks are planned to be installed in weak sud-doils,this forms the basis for assessment of the need for ground inprovment. The concepts for the analysis based on the bearing capacity and settlement criteria are escussed in detail together with the stability of the tank during earthquakes.A need for standardizing hydratest procedures is emphasized.\n\nA case study illustrating foundation strengthening by provision of granular piles to improve loose subsoil to support a 22 m diameter tank is presented the field control methods for successful ground improvement are also discussed.

Citation : Gopal Ranjan, Ravi Sundaram and Sanjay Gupta (2000), Geotechnical Design Criteria for Foundations of Large Diameter Tanks, Proceedings, Indian Geotechnical Conference, IGC-2000, Mumbai, pp 115-118.

Geotechnical Engineering Practice: Professionalism and The Law
Sanjay Gupta and Ravi Sundaram, 24-May-2000

Synopsis: The Practice of geotechnical engineering includes consultancy work as well as construction activities .The paper presents a discussion on what problems ail its practice administrstion and its consequences as well as remedial legal measures as per the Indian law. The need for professionalism is emphasized together with an outline of the steps taken by ISSMGE and IGS on professional practice issues and suggestions on statutory recognition to resolve the problems.

Citation : Sanjay Gupta and Ravi Sundaram (2000), “Geotechnical Engineering Practice : Professionalism and The Law”, Proceedings, Indian Geotechnical Conference, IGC-2000, Mumbai, pp 421-424.

 

Ensuring Reliability of Foundation Design Through Modern Geotechnical Investigation Techniques
Sanjay Gupta, Ravi Sundaram, Sorabh Gupta, 03-Apr-2000

Synopsis : Geotechnical engineering provides the vital input for design of foundations which is of paramount importance for reliability in the performance of civil engineering structures. The paper presents a discussion on how modern field investigation techniques and in-situ testing backed up by a thorough laboratory testing programme can revolutionize foundation design. A carefully planned and properly executed investigation can result in a greater degree of confidence in the design in additiona to cost effectiveness. 

Citation :  Ravi Sundaram and Sanjay Gupta (2000), Ensuring Reliability of Foundation Design Through Modern Geotechnical Investigation Techniques, Proceedings QUARS 2000, National Seminar on Quality Assurance and Reliability in Structures, Association of Consulting Civil Engineers (India), Coimbatore Centre.

Pile Foundations for Flyover (ROB) in Jaipur - Geotechnical Aspects
Sanjay Gupta and Ravi Sundaram, 25-Jun-1999

Synopsis: This paper presents the field experience of the authors in installing and testing diameter piles for an important projrct in the infrastructure sector in jaipur.Results of a geotechnical investigation conducted at the site are presented in conjunction with the results of load tests on initial and working piles.Load test results have been extrapolated using a hyperbolic model to assess the safe working load.

Citation : Sanjay Gupta and Ravi Sundaram (1999), Pile Foundations for Flyover (ROB) in Jaipur - Geotechnical Aspects, Proceedings Indian Geotechnical Conference - IGC - 99, Calcutta.

Foundations for Large Diameter Tanks : Case Studies
Gopal Ranjan, Sanjay Gupta and Ravi Sundaram, 21-Apr-1999

Abstract: Large diameter cylindrical welded steel tanks are commonly used to store large volumes of crude oil, petroleum products, hazardous chemicals, molasses, water etc. This paper presents case studies illustrating installation of large diameter tanks in different soil conditions. These case histories have been selected to illustrate the selection of foundation type, the analysis done and performance evaluations.

Citation : Gopal Ranjan, Sanjay Gupta and Ravi Sundaram (1999), Foundations for Large Diameter Tanks : Case Studies, Journal of The Institution of Engineers (India), Volume 80, November, 1999, pp 101 - 104.

Deep Foundations Under Artesian Conditions
Sanjay Gupta and Ravi Sundaram, 22-Apr-1998

Synopsis: Geotechnical investigations done at sites of bridges along the route of the kohalpur-Mahakali Highway in the terai region of western Nepal revealed the occuyyence of artesian groundwater flow in granular strata confined between clay layers.The paper discusses the methodology adopted for the geotechnical investigations.The concept for foundation design in such strata should consider three aspects-(a) bed boilong (quick condition) should not develop even after scouring, (b) during construction, minimum soil cushion thickness should be available above the artesian layer so that the artesian pressure does not puncture through, and (c) for long term stability, the bearing capacity at artesian level should be calculated using the effective overburden pressure.

Citation : Sanjay Gupta and Ravi Sundaram (1998), Deep Foundations Under Artesian Conditions, Proceedings, Indian Geotechnical Conference, IGC - 98, Delhi Vol.II, pp 133 - 140.

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.