Effective engineering solutions for drainage systems in peat soils

Andrey Nikitin,Olga Zaborskaya,A Zheltenkov,A Mottaeva

doi:10.1051/e3sconf/202016401019

Abstract

The article describes the feasibility of using a stone-free drainage system for water depression in peaty soils. The purpose of the research is to develop economical and technological engineering solutions for drainage in peat soils. A specimen of a stone-free drainage system, including a perforated corrugated pipe 150 mm in diameter and expanded polysterene pellets as aggregate, was studied in laboratory conditions. Geotextile filters were wrapped around both the aggregate and the drain pipe. The drainage system specimen was subjected to a load equivalent to that applied by 1 to 4 m of backfilling sand. The study established high deformability of the drain pipe and the pelletized expanded polysterene aggregate, as well as a considerable decrease in the aggregate water permeability. Тhe burial depth of a typical stone-free drainage system shall be limited by 2.5 m. The article shows that the presence of clogging particles in drain water may lead to a considerable decrease in permeability of geotextile filters on drain pipes. The proposed design of stone-free drainage system in peaty soils ensures lower material consumption, cost, and workload. To reduce deformations of stone-free drainage system structural components, pipes and aggregate of non-yielding (stiff) materials shall be used.

Highlights

Construction on peaty soils is often associated with water depression activities
The recent practice is to have pipes wrapped in geotextile fabric. It has high water permeability, chemical stability, and soil tightness, which reduces silting of drain pipes [1-5]
Testing has shown that extruded polystyrene foam is less compressible under load, which enables its use at a greater drain burial depth

Summary

Introduction

Construction on peaty soils is often associated with water depression activities. Where peat thickness is small, drains are placed on mineral bottom. Crushed stone is used as pipe cover (drain aggregate). The recent practice is to have pipes wrapped in geotextile fabric It has high water permeability, chemical stability, and soil tightness, which reduces silting of drain pipes [1-5]. Operation of typical drainage systems has shown that their water intake capacity will decrease drastically with time. In some cases such drains stop working altogether requiring re-installation. A drain design excluding crushed stone cover has come into use. It allows reducing labour input and improving cost efficiency (Figure 3). Geotextile filters are installed both over the aggregate's outer envelope and around the drain pipes. This design makes the drain system easier to install and maintain

Laboratory experiments

Conclusions