Device and method for remodeling soft clay samples based on vacuum combined electroosmosis

Abstract

The invention discloses a remoulding soft clay sample preparation device and a remoulding soft clay sample preparation method based on a vacuum combined electron-osmosis effect. Nonwoven geotextile, a gravel layer, a sand mat layer and an electron-osmosis cathode are sequentially paved on an osmosis drainage base; the upper and lower ends of a latex film are respectively turned outward and sleeved on a sample loading solidification cylinder and are fixed with the osmosis drainage base by a bolt through a flange; a water vapor separation cylinder is provided with an electric contact vacuum member and is connected with the osmosis drainage base and a vacuum pump respectively through an air pipe; slurry is poured into the designated height of the sample loading solidification cylinder, and an electro-osmosis anode is put in; and the electro-osmosis anode and the electro-osmosis cathode are respectively connected with a programmable direct-current power supply by wires. Under the combined effect of vacuum negative pressure and electro-osmosis, the drainage solidification speed of a soil body is increased, and the solidification stress level in a soil body sample preparation process can be adjusted. According to the device and the method disclosed by the invention, the size of a sample tank is reduced, and meanwhile, the number of sample preparation each time is increased by preparing multiple groups of soil samples; the device has a simple structure and is convenient for operation and sample taking; and the sample preparation period is short, and secondary cutting, disturbance and waste of soil samples are effectively avoided.

Description

technical field [0001] The invention relates to the technical field of sample preparation in geotechnical engineering, in particular to a remodeling soft clay sample preparation device and method based on vacuum combined electroosmosis. Background technique [0002] In the field of geotechnical engineering technology, in order to obtain the basic physical and mechanical properties of soil and its response characteristics under complex stress conditions, it is often necessary to carry out relevant laboratory test research. Undisturbed soil samples have in-situ stress state and original structure, which can truly reflect various mechanical properties of soil under natural conditions, and are often the most ideal choice for indoor experiments. However, the undisturbed samples have problems such as complicated sampling equipment and operation process, stress release and dehydration problems during transportation and storage, and high cost. In actual operation, remolded soil samp...

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Problems solved by technology

The pressurized consolidation method appeared earlier, and the static load was often applied by the pressure chamber of the triaxial instrument to accelerate the consolidation of soil samples. It mainly has the following disadvantages: (1) The loading equipment is heavy, and it cannot be used when the sample volume is large. Ensure the uniformity of consolidation; (2) The operation is more complicated, the air bubbles entering the mud during the operation are not easy to discharge, and the saturation degree of the soil sample is difficult to meet the requirements

The former pre-compression box cannot be disassembled, and sampling is more difficult; while the latter increases the vertical drainage channel, the vacuum seepage field inside the soil is also complicated, which changes the consolidation stress state of the soil.

In order to increase the number of samples prepared at one time, the size of the soil samples prepared by both methods is large, which affects the balance of the samples. At the same time, in order to prevent the disturbance of the soil samples during the cutting process, the soil samples taken out are often much larger than the test samples. required size, which inevitably leads to waste of soil samples

In addition, in order to speed up the consolidation of the soil, the vacuum degree is above 80kPa. If the actual loading stress in the subsequent indoor test does not reach the stress level during sample preparation, the soil will be in an over-consolidated state during the test, which will affect the test results. have a big impact

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