一种新型南55渗透仪研制及工程应用

Development and engineering application of a new type of Nan-55 permeameter

南55型渗透仪广泛用于测定细粒土渗透系数,结构简单,操作方便,但在原状土渗透试验中,由于环刀与试样之间密合不理想常引起侧壁渗漏,极大影响试验结果,甚至试验失败。为解决侧漏问题,通过采用对开环刀结构设计,研制了一种新型南55渗透仪,利用不透水的凡士林等膏状物充填试样与环刀之间的空隙,阻断侧漏通道,并在整体结构上沿用了南55渗透仪的基本框架,具有结构简单和操作方便的优点。同时,对测试结果可靠性进行了试验分析,结果表明,新型南55渗透仪有效解决了侧壁渗漏问题,测试的原状土渗透系数具有较高的精确度和稳定性,远高于南55型渗透仪,具备在实验室推广的前景。

The Nan-55 permeameter is widely adopted to determine the coefficient of permeability for fine-grained soils because of its simple structure and easy operation.However,for the permeability tests on undisturbed soil samples,the poor contact between the soil samples and the ring cutter may result in leakage of sidewalls and wrong test results.A new type of Nan-55 permeameter with split ring-cutter structure is developed in order to solve the leakage problem of sidewalls.The side leakage channel between the samples and the ring cutter is blocked by the paste such as Vaseline.What is more,the new-type Nan-55 permeameter has advantages of simple structure and easy operation by adopting the basic structure of the Nan-55permeameter.At the same time,the reliability of the permeability test results is analyzed,and it is shown that the new-type Nan-55 permeameter effectively overcomes the leakage problem of sidewalls.The coefficient of permeability for the undisturbed fine-grained soils measured by the new-type Nan-55 permeameter has a high accuracy and stability,which are much higher than those measured by the Nan-55 permeameter.The new type Nan-55 permeameter has the prospect to be popularized in the laboratory.