Based On New Paddy Field Projects Of Physical Properties

Nowadays, lacking of paddy fields is the reason why the cultivating is so difficult in hilly area, which can not appease the normal agricultural production. New paddy field is an important part of the slope remediation and also is an important step to improve the quality of cultivated land. With the Ministry of Land, 2014 No. 18 document "Strengthening the management and control to implement the most stringent farmland protection system of notification" release, it is Confirmed paddy field gap that is gradually increasing. So the new paddy field has an important role to improve the status of hilly region. In previous studies, the new paddy fields study less both local and overseas. Some studies mainly aimed at dry land reform after paddy field surface changes on the physical and chemical properties. Scarcely engineering design of the new paddy propose appropriate standard article. Therefore, this article will explore the hilly area of the new soil physical properties, soil shear strength, slope stability and soil surface penetration and other factors paddy field location and area sampling points. Simultaneously, it will be given engineering a proposal and the corresponding technical points.This paper discussed the development of Jurassic Shaximiao from gray brown purple soil for the study. Collected five samples of different tillage by direct shear test method, variable head permeability analysis plots in the region’s various traits. By taking four different specifications of the slope, the slope of each size were collected eight different slope, calculated using slice method of slope, slope stability characteristics obtained. According to the elements of the new paddy field, the corresponding engineering design is proposed. The results are as follows:(1) Distribution of soil physical propertiesSoil bulk density plots descending order: upland rotation> vineyards> abandoned land> vegetable land> orchard; Gravel content descending order: abandoned land> orchard> vineyards> vegetable> upland rotation. Particle size of less than 0.002 mm clay content is: upland rotation > vineyards> vegetable land > orchard> abandoned land. Particle size of greater than 0.002 mm clay content is: abandoned land> orchard> vegetable> vineyards> upland rotation, counterproductive compared to clay content. Fractal dimension gradually reduced from paddy fields to abandoned land, and the correlation coefficient is also significantly reduced. All the samples had minor differences in liquid limit, plastic limit and plasticity index.Significantly, there are relationship between permeability coefficient and gravel content. With the increase of gravel content, permeability coefficient increases. When the gravel content less than 20% change in the permeability change between 10-8 to 10-4 magnitude; when the gravel content exceeds 20%, mainly, permeability transition occurs in the permeability coefficient between 10-3 and 10-1. Compared with the results of gravel content, the results of permeability coefficient and soil bulk density is the opposite. The greater the density, the smaller the permeability coefficient is. When the bulk density is greater than 1.4~1.5g/cm3, the permeability coefficient is small, and it will focus on the permeability coefficient change between 10-8 and 10-4 magnitudes. When the bulk density of less than 1.4~1.5g/cm3, the permeability coefficient becomes large, the change in permeability between 10-3 and 10-1 magnitude change, and it will appear at this point jump on. In addition, the permeability coefficient and cropping patterns are also related, permeability coefficient in paddy cultivation(B3, B4) <upland Rotation(B1) <dry land or abandoned land(B2, B5).(2) The shear characteristics of soil and slope stabilityWith the increase of shear displacement, the shear stress increases. Under these conditions of moisture content(7%, 13%, 19%), the shear stress increases rapidly in the shear displacement of less than 1mm. when the shear displacement more than 1mm, shear stress growth has slowed; when the water content was 25%, the shear stress with shear displacement is slow. When the shear displacement greater than 3mm, shear stress changes with shear displacement began to decrease; while shear displacement is greater than 4mm, shear stress increment smaller, almost stabilized. In the vertical pressure of 100 kPa or 200 kPa occurs, it appears residual shear strength. In the B1 and B5 Vegetable abandoned land in the moisture content of 7%, the vertical pressure of 100 kPa time, there has been softening, but not very obvious signs of softening. With the increase of moisture content in the same shear displacement, shear stress corresponding gradual decrease. The maximum shear stress occurs in an aqueous corresponding rate of 7%, and the minimum in water content was 25%.The factor of influence slope stability from strong to weak was cohesion, internal friction angle, and slope gradient. Steeper slope, the smaller the safety factor of slope is. The larger the angle of internal friction, the greater the safety factor of slope stability is. The greater the cohesion, the greater the safety factor of slope stability is.(3)The layout and design of the new paddyThis chapter describes the two aspects in the new paddy field engineering layout and engineering design. According to the survey, paddy field area terrain slope should be less than 25° and the field surface slope less than 6°, which a single block of paddy field area of not less than 100m2. The plots could be divided the drylands into five types, such as mesa dry land, gentle slope dry land, paddy field dry store planning, upland dryland crop rotation and reclamation dry land. It is suitable for new paddy field while the position of the lower terraces, major soil capacity to 1.4g/cm3, gravel content of less than 5%, clay content greater than 25%, the plasticity index of greater than 12% and permeability coefficient control at less than 10-5 orders of magnitude. Engineering design includes debris removal, dry finishing, building ridge, soak tillage plots and water soil preparation.