Introduction 

Initial geotechnical investigation for a multistoreyed residential complex in south Delhi indicated substantial variation in the depth to rock across the site. To evaluate the trend of the rock profile, seismic refraction tests were performed. 

The paper presents the effective use of geophysical tests to characterize the stratigraphy for effective geotechnical assessment of the site.

Citation: 

Ravi Sundaram, Sorabh Gupta and Sanjay Gupta (2023), "Geotechnical and Geophysical Characterization - Case Study of a Site with Steeply Dipping Rock", Soil Behaviour and Characterization of Geomaterials, Proceedings of Indian Geotechnical Conference IGC-2021 (Volume-1), K. Muthukkumaran et.al (eds), Springer Nature, Singapore, pp 209-218.

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.

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.

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

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 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.

Abstract 

An 85-m high bungy jumping tower, set to be the highest in India is under construction in Rishikesh. Located on right bank of River Hule at Shivpuri between the North Almoda Thrust and the Saknindhar Thrust, rocks in the area are sheared and disturbed. The paper presents the geotechnical conditions at site and the foundation system for the tower. Appropriate slope stabilization measures were implemented for long-term stability.

Citation

Abhay Gupta, Ravi Sundaram and Sanjay Gupta (2022), “Foundation for an 85-m High Bungy Jumping Tower at Rishikesh”, Proceedings, Indian Geotechnical Conference IGC-2022, Dec 14-16, 2022, Kochi

 

Abstract

To determine the depth of an existing bridge foundation for construc-tion of an underground rail corridor, parallel seismic tests (PST) and low-strain pulse echo method (PIT) were used. Since the tunnel alignment crosses an old bridge, the depth of the bridge foundations was evaluated by non-destructive geophysical tests to assess the impact of tunnelling on the existing structure. The side of the piles were exposed to perform the pile integrity test. A borehole was drilled adjacent to two piles and cased with a PVC pipe. The paper presents results of the parallel seismic tests and PIT conducted on two piles below the bridge abutments. The test results confirmed that the pile lengths ranged from 8 to 9 m. 

Citation 

Ravi Sundaram, Sorabh Gupta and Lakshmana Rao Mantri (2022), “Determining Depth of Foundation of an Existing Bridge using Geophysical Non-Destructive Tests – A Case Study”, Proceedings, Indian Geotechnical Conference IGC-2022, Dec 14-16, 2022, Kochi.

 

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

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

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.

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.

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

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

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.

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.

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.

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.