Page - 1234 - in Book of Full Papers - Symposium Hydro Engineering

UPGRADING THE PERFORMANCE OF POORLY COMPACTED EMBANKMENT FOUNDED ON SOFT CLAY USING SECANT AND STABILITY PILES SYSTEM* Ashraf A. El-Ashaal and Alaa A. Abdelmotaleb Geotechnical Engineering Professor, NATIONAL WATER RESEARCH CENTER EGYPT 1. INTRODUCTION The investigation of soil improvement of problematic soils as foundation of soil embankments drew the attention of many researchers. Many techniques have been developed to overcome the negative impact of such problematic soils. In the case under investigation, the presence of deep soft clay layer form an obstacle for adapting the available techniques like soil fracturing and vibro replacemet. Control of seepage water through the soil media was investigated and discussed in many research works. The automated digging apparatus with extensive support facilities required to construct plastic concrete diaphragm wall around Sizewell B. power station at UK was described in [1]. Typical examples of walls to prove the adaptability and advantages of the secant bored pile wall method were summarized in [2]. Field studies have indicated the importance of the monitoring activities in understanding the interaction between the utilized pile and the surrounding soil [3]. Based on the rapid progress in analytical and monitoring techniques, graphs for the design of laterally loaded piles in clay was presented in [4]. In the present work, a stabilizing system of an embankment of one of the major canals north of Egypt was monitored and the collected data are discussed. The soil properties, the embankment cross-section, and the design concept of the proposed upgrading system were pointed out by [5]. The Atlas pile type is used in constructing both seepage control and stability improvement systems. The cast insitu screw piles with very rough shaft (Atlas type) proved to be the most suitable pile type to handle the presence of deep soft clay deposits. A complete review of the developments in Atlas type design and the main factors affecting its performance is in [6]. The monitoring system utilized for evaluating the seepage pattern inside the embankment and the performance of the cutoff secant piles are discussed in the present paper. The main conclusions that prove the effective performance of the tested system are pointed out. 1234