Diffusion Model of Parallel Plate Crack Grouting Based on Foaming Expansion Characteristics of Polymer Slurry

Polymers as a new chemical grouting material have been widely used in fractured rock mass; however, the understanding of polymer diffusion characteristics still needs to be further improved. In order to study the diffusion mechanism of foamed polymer slurry in rock fissures, the radial diffusion model of polymer single crack grouting is derived in consideration of the factors such as grouting volume, crack width and expansion rate. The influence of different factors on slurry diffusion radius, diffusion pressure and flow rate is analyzed, The diffusion model is verified by finite element numerical simulation. The findings show that (1) The results of slurry diffusion radius, pressure and velocity distribution at different times under different working conditions in the present model are in good agreement with the analytical solution; (2) The diffusion pressure is directly proportional to the grouting volume and expansion multiple, and inversely proportional to the crack width. In addition, diffusion pressure decreases with the increase of diffusion distance, and the pressure at the corresponding distance increases slowly with time, and finally tends to be stable; (3) For the same section, the radial velocity decreases slowly with the increase of time; for different sections, the flow velocity increases sharply with the increase of the distance between the section and the central axis of the grouting hole.

Optimal Design and Numerical Analysis of Soil Slope Reinforcement by a New Developed Polymer Micro Anti-slide Pile

As a new material, polyurethane polymer has been widely used in engineering in recent years due to the excellent engineering mechanical properties. Based on the characteristics of this material, a multi pipe grouting micro anti-slide pile is proposed, which is formed by using polymer slurry as grouting material. Compared with traditional anti-slide pile, the polymer micro pile has the advantages of strong applicability, no water reaction, small disturbance, fast construction, economy and durability. As a flexible retaining structure, polymer micro-piles can strengthen the slope by cooperating with the forces. However, there is no report on the reinforcement of slope by polymer micro piles at present. In this paper, a three-dimensional multi row polymer micro piles model for slope reinforcement considering different embedded depth and pile location is established. Safety factor, thrust force of landslide behind pile, length of pile and mises stress are taken as four factors to evaluate reinforcement effect, the optimal reliability of polymer micro anti-slide pile for slope reinforcement is evaluated by giving different weight values to each factor through multi factor comprehensive evaluation method. The safety factor of slope (Fs), landslide thrust behind pile and mises stress of pile are analyzed under different embedded depth (le) and pile position (px). The results show that the best embedded depth is about1/8 − 1/12 of the horizontal length of the landslide behind the pile when multi row polymer micro piles are used to reinforce the slope; the optimum position of pile arrangement is 0.55–0.65 times the slope length from the top of the slope.

Study on rheological properties of polymer grouting materials with different expansion rates

Non-water reactive polymer grouting technology is an important means to control water-induced engineering disaster emergency rescue. However, the time-varying viscosity of polymer slurry and the expansion force of slurry reaction are the main factors affecting the grouting treatment effect. Therefore, it is necessary to study the time-varying viscosity of polymer slurry and the expansion force of slurry reaction. Firstly, the expansion rate of polymer slurry with different expansion ratio is tested and checked by the self-made expansion rate measuring cylinder. Then, the reaction expansion force and viscosity of polymer slurry with different expansion ratio are tested and studied by the expansion force testing device and NDJ-5T digital rotational viscometer. The results show that the expansion rate of polymer slurry used in this paper is basically the same as the factory instructions At the same time, the viscosity of polymer slurry increases exponentially with time, and the curve is steeper, that is to say, the viscosity increases rapidly with time.

Design and Engineering Application of Polymer Grouting Pore Layout Scheme for Expressway Pavement Diseases

In grouting technology, after choosing the type of grouting fluid needed for grouting, the next most important step is the layout of grouting holes, that is, grouting hole type and hole spacing. Reasonable arrangement of grouting holes and hole spacing can not only achieve the desired reinforcement effect, but also save unnecessary economic expenses. For this reason, the effective diffusion radius of slurry is firstly determined considering both the characteristics of polymer slurry and the pore structure of injected medium. Based on this, the distance between holes (triangular and rectangular) is determined. Finally, the grouting design parameters of this design scheme are applied to the disease area of Nanping Expressway in Shenzhen. The deflection value before and after grouting is detected by falling weight deflectometer (FWD). The results show that the grouting design parameters can achieve better grouting effect.

Evaluation of the quality of pile foundations by different methods

At the present time, in Astana city is going on works by construction public transport system LRT (Light Railway Transport). LRT is an overhead road with two railway lines. The first stage of construction is including construction of overhead road (bridge) with 22.4 km length and 18 stations. The foundation of bridge is the bored piles with cross-section of 1.0-1.5 m and length of 8-35 m. A design bearing capacity of pile is 4500-8000 kN. Chinese drilling rigs Zoomlion was used for soil boring without casing. A polymer slurry is used to maintain the walls of boreholes in sand and gravel soils. In these conditions very important point is the integrity of concrete body of each bored piles. For checking the integrity was used two methods – the Low Strain Method and the Cross-Hole Sonic Logging. The aim of this paper is finding the advantages and disadvantages of each method which applying on testing site.

SYNTHESIS OF AMINE-CONTAINING POLYMERIC MICROSPHERES BY SEED COPOLYMERIZATION FOR APPLICATIONS IN BIOTECHNOLOGY

This paper presents the results of studies of seed copolymerization of glycidyl methacrylate with ethylene glycol poly(glycidyl methacrylate) on seed particles in order to obtain partially crosslinked polymer microspheres with a diameter of about 3.5 microns for use in immunochemical reactions, as carriers of bioligands. The physico-chemical properties of polymeric microspheres obtained under different conditions were studied by the following methods: the diameters of the particles - by electron scanning and light microscopy; the wetting angle - bу the method of "lying droplets"; the sedimentation velocity - by the macromethod in a capillary tube by the movement of the (polymer slurry)/water phase boundary (buffer solution); the zeta-potential - by dynamic light scattering. Having studied the physical-chemical properties of all polymer slurries we concluded that the optimal particles to create on the basis of their diagnostic test systems with high sensitivity working on the principle of latex agglutination reaction are poly(glycidyl methacrylate) particles with equal percentage of glycidyl methacrylate and ethylene glycol dimethacrylate aminated with hexamethylendiamine in the environment of n-propanol, because they have a sufficient number of amino groups and do not lose their sedimentation properties after all stages of the synthesis.

Laboratory assessment of the effects of polymer treatment on geotechnical properties of low-plasticity soil slurry

A laboratory study was undertaken to assess the effects of polymer treatment (PT) on the geotechnical behaviour of a low-plasticity slurry. PT was undertaken on the material using a high molecular weight polyacrylamide polymer. Slurry consolidometer and triaxial testing were undertaken to compare the geotechnical behaviour of the material following PT, compared to an untreated (UT) condition. The material was prepared from a slurry state in a nonsegregating condition, to enable comparison of uniform samples. Testing indicated that PT resulted in lower final consolidated densities at a given magnitude of effective stress, while increasing the rate of consolidation and hydraulic conductivity. Triaxial testing indicated that PT material, when sheared, appeared to exhibit a different critical state line (CSL) than UT material. The PT CSL was higher in void ratio terms than the UT CSL, and with an increased compressibility. Both PT and UT material exhibited undrained shear strengths consistent with the state of the specimen with respect to that material’s CSL. PT material exhibited higher undrained shear strengths at a given density. All the effects observed following PT appeared to persist across a wide range of effective stresses.