Design the outlet protection for a temporary slope drain with a diameter (D) of 300mm, smooth internal sidewall, and design discharge of 100L/s. Given D = 300mm and Q = 100L/s, the recommended mean rock size as obtained from Table 2 is d50 = 300mm and L = 1.7m. Upstream width of the rock pad, W1 = D + 0.6 = 0.9m (see Figure 1).

After the weight and “d” of each rock (except small rock, gravel) are determined, they need to be accumulated into sizes that would be held on a particular screen size such as 1.5 D50, D50, etc. The weights of the rocks that have a “d” greater than the screen size are accumulated and considered retained on the screen.

The thickness of the rock protection should be sufficient to allow at least two overlapping layers of the nominal (d 50) rock size. The thickness of rock protection must also be sufficient to accommodate the largest rock size. In order to allow at least two layers of rock, the minimum thickness of rock protection (T) can be

2024年11月30日 · Determining the correct size of riprap, represented by the median stone size (D50), is critical in hydraulic engineering projects to ensure stability and longevity of these structures. This calculator provides a quick and accurate way to calculate the required stone size for stabilizing slopes and channel beds. What Does This Calculator Do?

Most sediment and geotechnical analyses that quantify soil or rock gradations deal with rock and soil size in terms of diameter. However, riprap design often specifies rock size in terms of...

determining a design stone size, such that the stone is stable under the design flow conditions. The design stone size is the d50 stone diameter. Erosive forces of flowing water are greater in bends than in straight channels.

First, the required size of the riprap rock, known as D50, is calculated. Then, the dimensions of the apron are obtained from a table. The following equation is used to determine the Apron rock size, D50: Where: Tailwater depth is limited to between 0.4D and 1.0D. For example, if Tw is less than 0.4D then Tw = 0.4D.

Riprap shall consist wholly of hard, durable, dense natural rock. All stones in the riprap shall be well shaped, with no stone having a length more than 2.5 times its breadth or thickness (see Note 1 in Section 3.3). The mean diameter (D50) of the stone in …

Materials - Outlet protection may be done using rock riprap, concrete block or gabions. Thickness - The maximum thickness of the riprap layer shall be 1.5 times the maximum stone diameter for d50 of 15 inches or less; and 1.2 times the maximum stone size for d50 greater than 15 inches. Table 1 lists some examples.

筛分粒度就是颗粒可以通过筛网的筛孔尺寸，以1英寸（25.4mm）宽度的筛网内的筛孔数表示，因而称之为“目数”。 目前在国内外尚未有统一的粉体粒度技术标准，各个企业都有自己的粒度指标定义和表示方法。 在不同国家、不同行业的筛网规格有不同的标准，因此“目”的含义也难以统一。 因此，用目数来恒量抛光粉的颗粒大小是不恰当的，正确的做法应该是用粒径（D10，中位径D50，D90）来表示颗粒大小，用目数折算最大粒径。 如果大家看过日本关于磨料的标准JIS …