Filter design impacton drainpipe water intake capacity

Zaborskaya

2020

E3S Web Conf.

Self Cite

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.

Section: Introductionmentioning

confidence: 99%

Effective engineering solutions for drainage systems in peat soils

Zaborskaya

2020

E3S Web Conf.

Self Cite

“…Natural-state peat is water-permeable. Multiple surveys have proved that peat permeability significantly decreases after compaction [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

The drainage system performance in peat soil with permeability reduction

Zaborskaya

2019

E3S Web Conf.

Self Cite

Construction in waterlogged areas requires special design solutions and expensive site preparation works. Operating experience shows that the efficiency of drainage systems in peat soil decreases over time. This article describes factors to be taken into account when designing drainage systems in peat soil. It also summarizes the results of the laboratory surveys for peat and filling material permeability reduction over time. We used a laboratory box to study water permeability over time. In the experiment, we used poorly decomposed peat of natural structure and compacted peat. The study found that the water inflow into the drainage system decreased 1.5 to 1.7 times in the course of filtration. The greatest peat permeability reduction was recorded at the initial stage. The article demonstrates how the grain-size composition of sand used as backfilling affects its water permeability. In order to ensure normal operation of drainage systems in peat soil, one must consider the reduction of peat water permeability over time and clogging of sand filling when designing the said systems.

Vacuum consolidation for construction of motor road embankments in peat soil

IOP Conf. Ser.: Mater. Sci. Eng.

2019

One of the efficient methods to accelerate primary filtration consolidation of peat is vertical draining combined with vacuuming. This article presents the results of laboratory analysis of vacuuming impact onto the peat deformation rate in the bases of motor road embankments. It demonstrates that the duration of peat vacuuming increases and its efficiency decreases with the increase of pressure exerted by surcharge sand layer. The results of compression tests have shown that relative peat deformation after vacuum consolidation is 0.24…0.37; this means the deformation rate of the road base in the course of operation will be significantly lower. The effect of vacuum consolidation on peat settlement rate during motor road embankment construction was assessed by numerical simulation in PLAXIS software, which enables accounting for consolidation and creep processes in motor road base courses. The results of numerical simulation were used to compare the efficiency of preloading the peat using surcharge sand with the efficiency of vertical draining combined with vacuuming, considering the allowable embankment settlement rate during motor road operation. Due to a low settlement rate, the vacuum consolidation method ensures normal road operation and allows increasing the maintenance interval.