Assessment of rapid impact compaction in ground improvement from in-situ testing

Abstract

Ground improvement has been used on many construction sites to densify granular materials, in other word, to improve soil properties and reduce potential settlement. This work presents a case study of ground improvement using rapid impact compaction (RIC). The research site comprises the construction of workshop and depots as part of railway development project at Batu Gajah-Ipoh, Malaysia. In-situ testing results show that the subsurface soil comprises mainly of sand and silty sand through the investigated depth extended to 10 m. Groundwater is approximately 0.5 m below the ground surface. Evaluation of improvement was based on the results of pre- and post-improvement cone penetration test (CPT). Interpretation software has been used to infer soil properties. Load test was conducted to estimate soil settlement. It is found that the technique succeeds in improving soil properties namely the relative density increases from 45% to 70%, the friction angle of soil is increased by an average of 3°, and the soil settlement is reduced by 50%. The technique succeeds in improving soil properties to approximately 5.0 m in depth depending on soil uniformity with depth.

Keywords

cone penetration test / granular soil / compaction / rapid impact compaction / relative density / settlement / improvement depth / in-situ testing

References

[1] WangX-h, CuiK-y, WangZ-y, WangM-chan. Deduction and experimental investigation of constitutive relation of liquefaction of saturated sand [J]. Journal of Central South University of Technology, 2010, 17(6): 1376-1383

[2] ShiW-c, ZhuJ-g, ChiuC-f, LiuH-long. Strength and deformation behavior of coarse-grained soil by true triaxial tests [J]. Journal of Central South University of Technology, 2010, 17(5): 1095-1103

[3] PanH, ChenG-x, SunT, LiuH-long. Behaviour of large post-liquefaction deformation in saturated sand-gravel composites [J]. Journal of Central South University, 2012, 19(2): 547-553

[4] CharelsJ A, WattsK STreated ground engineering properties and performance [R], 2002Westminester, LondonCIRIA C 57296-101

[5] SerridgeC J, SyancO. Application of the rapid impact compaction (RIC) technique for risk mitigation in problematic soils [R]. IAEG, 2006294

[6] BraithwaiteE J, du PreezR W. Rapid impact compaction in Southern Africa [C]. Proceedings of the Conference on Geology for Engineering, Houghton, 199713-14

[7] MitchellJ M, JardineF MA guide to ground treatment [R], 2002Westminester, LondonCIRIA, C 57367-68

[8] WattsK S, CharelsJ AInitial assessment of a new rapid ground compactor [M], 1993LondonThomas Telford349-412

[9] KristiansenH, DaviesM. Ground improvement using rapid impact compaction [C]. 13th World Conference on Earthquake Engineering. Vancouver. Canada, 2004496

[10] National Cooperative Highway Research Program NCHRP.Cone penetration test [R], 2007AtlantaGeorgia Institute of Technology

[11] LunneT, RobertsonP K, PowellJ J MCone penetration test in geotechnical practice [M], 1997LondonBlacker Academic & Professional312

[12] BS 1377-9 Methods of test for soils for civil engineering purposes - In-situ tests.British Standards Institution [S], 1990

[13] MohammedM M, HashimR, SalmanF A. Effective improvement depth for ground treated with rapid impact compaction [J]. Scientific Research and Essays, 2010, 5(18): 2686-2693

[14] TanB K, BacheloR B. Foundation problems in limestone areas A case study in Kuala Lumpur, Malaysia [C]. Proc Int Symposium Weak Rock. Tokyo, 19811461-1463

[15] SchmertmannJ H. Static cone to compute static settlement over sand [J]. ASCE, Journal of Soil Mechanics and Foundation Engineering, 1970, 96(3): 1011-1043