III. GEOTECHNICAL ENGINEERING

B. ON GOING PROJECTS
3. Investigation and Design of High Embankment on Soft Ground using Flyash fill for bypass road from Kalindi Colony to Kalindi Kunj, New Delhi
Date of Start

May 2005
(i) Central Road Research Institute, New Delhi (R)
(ii) Public Works Department, Government of Delhi (S & I).

 

Present Status and Progress
The Public Works Department (Division XX), Government of Delhi has taken up construction of Kalindi Bye pass from Kalindi colony, Ring road to Kalindi Kunj. This new road alignment takes off from the Ring road near Kilokri (Kalindi colony) and passes through Khizrabad, Jogabai, Okhla and Jasola villages and would be linked to NH 2 (Mathura Road). This alternative road is expected to decongest the Mathura road. The major part of this road alignment is located in flood plain of Yamuna River and is situated close to the river.

The assigned work of CRRI is:
1. Drilling boreholes at different locations up to hard strata.

2. Collection of undisturbed and disturbed soil samples from all boreholes and conducting relevant laboratory tests on representative soil samples as per IS: 2720.

3. Conducting Standard Penetration tests (SPT) at different depths in the borehole.

4. Conducting Dynamic Cone Penetration Tests (DCPT) and Static Cone Penetration Test (SCPT) at selected locations.

5. Interpretation of the field and laboratory test results to make recommendations for ground improvement.

6. Design of the embankment section incorporating fly ash as construction material.

7. Settlement analysis and suggesting remedial measures for ground improvement if required.

Presently the work on this project is under progress. The alignment of the proposed road starts from Ring road near Kalindi Colony (NOIDA Toll bridge embankment – Chainage 0 km) and ends at Kalindi Kunj. The total length of the road alignment is about 6.3 km of which initial 3.6 km has been investigated. Fly ash is being used as embankment fill material for construction of this road. During monsoon season, the floodwater from the Yamuna River and the sewage from adjoining residential colonies form ponds in the proposed road alignment. Fly ash has been used as embankment fill material in pond sections.
 
Findings/ Conclusions

• The sub soil stratum in the proposed ailment of Kalindi Bye pass predominantly consists of “poorly graded fine sand (SP)’. Further at shallow depths (up to about 3 m). this material was observed to be in loose state especially in between the chainage 0.8 km to 2.5 km. However this layer is devoid of clayey soil.

• Sand layer between 3 m to 15 m depth was found to be loose to medium dense. Sub-soil below 15 m depth was found to be in a densely compacted state having ‘N’ values in excess of 20. The results of SCPT tests also confirm this finding.

• Berm width equal to 3m and height 4.1m be provided by the river side of the embankment from chainage 2150m to 3000m.This is essential to prevent any failure of embankment side slope during sudden draw down conditions.

• The settlement of the embankment in the total reach from chainage 0+0 to 3+600m was computed to be between 7cm to 14.5cm. Of this maximum settlement (about 14.5cm) is expected to occur in the reach between 1+600 to 2+000m.

• The total construction period of the project is expected to be above two years as the sub-soil under going settlement is mainly sandy type, this settlement would occur during the construction phase itself.

 
Recommendations
• It is suggested that settlement of the embankment mark to be monitored. This can be achieved by installing permanent bench away from the road alignment and observations points all along the embankment and under taking regular leveling work of determining the spot levels of the observation points.

• As suggested earlier vide our letter No. CRRI/GTE/PWD dated 24.1.2005, three m vide berm shell be provided on the Yamuna river side from chainage 1+600 to 3+000m.

• In future, it is recommended that before taking up embankment construction, dewatering should be undertaken before taking up construction. In case dewatering is not feasible, it is suggested that backfill material to be placed inside standing water should be non-plastic granular material of maximum particle size less than 75 mm with uniformity coefficient not less than 10. It should be placed by end tipping in accordance with clause 305.4.6 of MoRTH specifications. Direct dumping of flyash in ponded water may be avoided.