ISO 18325:2015 pdf download

ISO 18325:2015 pdf download

ISO 18325:2015 pdf download.Geosynthetics — Test method for the determination of water discharge capacity for prefabricated vertical drains
1 Scope
This International Standard specifies a test method for determining the water discharge capacity of prefabricated vertical drains (PVDs), which can be used for conformance and acceptance testing.This is an index test.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5813, Water quality — Determination of dissolved oxygen — Iodometric method
ISO 9862, Geosynthetics — Sampling and preparation of test specimens
EN 15237, Execution of special geotechnical works — Vertical drainage
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 prefabricated vertical drain
drainage composite with a rectangular cross-section, with a width of typically 100 mm installed vertically into soil to provide drainage for accelerated consolidation of soils usually consisting of a central core with a channel system surrounded by a filter sleeve or with a filter adhered to it
Note 1 to entry: Other wordings like wick drain, band drain, strip drain are also used.
3.2 confined length
length of the part of the specimen exposed to pressure
3.3 filter length
length of the filter around or on the specimen
4 Principle
The factors affecting the discharge capacity of PVDs measured according to this International Standard are limited to the intrusion of the filter into the core linked to the filter stiffness, the drainage core stiffness, creep and geometry of the core to some extent and creep of the geotextile filter to some extent, confining pressure, and hydraulic gradient. PVD is enveloped by a flexible rubber membrane to simulate the deformation of the geotextile filter into the core structure and the discharge capacity is determined in straight and buckled conditions.
5 Apparatus and materials
5.1 Discharge capacity apparatus
5.1.1 The discharge capacity apparatus satisfies the following requirements.
a) The apparatus shall be capable of maintaining a constant head loss at different water levels, at least those corresponding to hydraulic gradients of 0,1 and 1,0, simulating the pressure arising from the earth mass when PVDs are mounted vertically within the ground to serve as discharging interstitial water, and testing PVDs in straight and buckled conditions.
b) The apparatus is mainly comprised of a pressure cell, a water supply portion (see Figure 1) and buckling device (see Figure 2). The buckling device is used to simulate the deformation of PVDs due to the relative compression in highly compressible soils. The pressure cell shall be capable of inserting the buckling device and maintain mounted specimens in straight and buckled conditions.
c) The distance between the two slots used to insert the specimen in the cell shall be (300 ± 10) mm.