Calling For: Slurry Wall Solutions

Abstract

Slurry cut-off walls are increasingly being used to control groundwater flows for geo-environmental or geotechnical purposes. The most important performance criteria of slurry cut-off walls are strength and permeability. This criterion makes it costly and time consuming. The objective of this problem statement by HSL Constructor Pte Ltd is to create an open platform for renowned international consultants (individual / firm) to submit a proposal on an alternate solution for cement bentonite slurry cut-off wall that overcomes the existing limitations.

Introduction

The proposed project site is located in South East Asia and it includes the full-scale construction of cement-bentonite slurry wall which acts as hydraulic containment barrier. The proposed slurry wall shall be 900mm thick, 30-35 metres deep and extends for a stretch of about 10 Kilometres. Slurry wall shall be terminated with a minimum penetration of 2m into the residual soil (SPT >= 100)

Specification Criteria of the above cement bentonite (C-B) wall:

1. Hydraulic conductivity / permeability criteria less than 1 x 10^-9 m/s

2. Unconfined Compressive Strength (UCS) - greater than 100KN/m2 and less than 300KN/m2

Limitation of slurry cut-off walls

· C-B wall could be produced to the required strength by adjusting its cement content which in turns influences the hydraulic conductivity and vice versa if bentonite content is adjusted. Thus, it is hard to ensure in-situ integrity over a full extent of major C-B wall.

HSL also considered the option of providing impermeable sheet (Geo membrane or HDPE) which was considered technically not feasible because of the difficulty of installation and inadequate keying into residual soil.

· Other slurry wall options like Plastic Concrete/ Soil Bentonite / Soil-Cement-Bentonite were not suitable due to other constraints.

Problem Statement

Addressing all limitations of a cement bentonite slurry wall in terms of permeability, durability and constructability, a suitable alternate/feasible/cost-effective option for slurry cut-off wall shall be developed and submitted including but not limited to the following considerations.

1. 1. Hydraulic conductivity / permeability criteria less than 1 x 10^-9 m/s
2. 2. Unconfined Compressive Strength (UCS) - greater than 100KN/m2 and less than 300KN/m2

Submittals & Remuneration

We welcome suggestions of alternate solutions for the mentioned problem statement and please contact us with your detailed profile/track records on or before 31st Jan 2018 via email. Remuneration will be commensurate with the professional proposal that meets our objective and specification criteria.

Contact Details Removed - Cr4 Admin