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.

TECHNICAL PAPERS
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.

Dynamic Response of Hard Clays of the Pir Panjal Trap
Sanjay Gupta, Ravi Sundaram, V.D. Miglani, 26-Jun-1997

Synopsis: Forced vibration tests were conducted as per IS:5249 in conjunction with repeated triaxial tests at a site in Pampore (Jammu & Kashmir). The soils at the site consist of hard over-consolidated desiccated silty clays of the Pir Panjal Trap. The test results indicate a very good dynamic response and also an increase in dynamic soil parameters with depth. Values of coefficient of uniform elastic compression, coefficient of uniform elastic shear and dynamic shear modulus measured from the field tests, as well as the laboratory tests are reported here to illustrate the dynamic response of the hard silty clays of the Pir Panjal Trap.

Citation :  Ravi Sundaram, Sanjay Gupta & V.D. Miglani (1997), Dynamic Response of Hard Clays of the Pir Panjal Trap, Proceedings, Indian Geotechnical Conference, IGC - 97, Baroda, pp 471 - 474.

Cement Grouting in Delhi Silt - A Field Study
Sanjay Gupta, Ravi Sundaram, T. Ramamurthy & S.N. Sinha, 15-Jun-1997

SYNOPSIS : Loose alluvial sites of Delhi can be successfully grouted using cement slurry. The paper presents a case study wherein the cement grouting was done to strengthen the foundations of a three storeyed building bearing on loose “Delhi Silt”. Details of the pressure grouting are presented together with the grout consumptions at various intake points. After grouting, the building was load tested to confirm the efficacy of the ground improvement.

Citation : Sanjay Gupta, Ravi Sundaram, T. Ramamurthy & S.N. Sinha (1997), Cement Grouting in Delhi Silt - A Field Study, Proceedings, Indian Geotechnical Conference, IGC - 97, Baroda, pp 255 - 258.

 

Gravel Piles: Construction and Field Testing
Sanjay Gupta and Ravi Sundaram, 19-Apr-1996

Abstract: Construction methodology for installation of gravel piles by the non-displacement technique (i.e. boring method) is discussed in the paper. Two case studies are also presented. The first one illustrates successful application in loose sandy strata at a site in the Indo-Genetic Alluvium. At this site, 400 mm dia stone columns were used to improve the soil beneath 22 m dia tanks. Load tests using different spacing between trial stone columns was used to optimize the design. The second case study relates to stone columns installed in marine clay in coastal Andhra Pradesh.

Citation : Sanjay Gupta and Ravi Sundaram (1996), Gravel Piles: Construction and Field Testing, Proceedings, Seminar on Piles, Indian Geotechnical Society, Delhi Chapter, pp 72-81.

Dynamic Characteristics of Collapsible Aeolian Sands
Ravi Sundaram and Sanjay Gupta, 05-May-1995

Synopsis: Forced vibration tests were conducted as per IS 5249 at a site in north-western Rajasthan. The soil at the site are meta-stable aeolian sands, piled up in the form of sand dunes. The test results indicate that, at shallow depths, in the loose to medium dense sands which are in the unstable part of the dune, the response under dynamic loading is poor. The two peaks in the amplitude-versus frequency curve suggest that the soil structure was probably collapsing and the sands were re-arranging into a more compact state. Tests were also conducted on the deeper relatively more stable soils. The test results were effectively used to design dynamically loaded foundations.

Citation : Ravi Sundaram and Sanjay Gupta (1995), Dynamic Characteristics of Collapsible Aeolian Sands, Proceedings, Indian Geotechnical Conference, IGC-95 Bangalore, pp 387-389.

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.