Appts. for setting up indoor water soil conservation model

[0019] The device for establishing an indoor soil and water conservation model proposed by the present invention has the following structure: image 3 As shown, it includes a rain shower 11 , a awning 14 , an underlying surface model 15 , a sampler 19 and a runoff bucket 16 . The rain shower 11 is placed on the top of the bracket 13 , the rain shelter 14 is placed in the middle of the bracket 13 , and the underlying surface model 15 is placed at the bottom of the bracket 13 . The rainfall device 11 is composed of a main pipe 26 and a branch pipe 27, the main pipe is square, a plurality of branch pipes are arranged in parallel in the main pipe, and the main pipe and the branch pipes are connected with each other. One side of the main pipe 26 is provided with a water inlet pipe 12, and the opposite side is provided with a sewage pipe 25. The underlying surface model 15 includes a slope surface 20, a side wall, a movable side clapboard 21 and a movable rear clapboard 23. The slope surface 20 is the bottom of the model, and the four sides of the model are the side wall 22, the movable rear clapboard The bulkhead 23 , the movable side bulkhead 21 and the front sidewall 18 . The sampler 19 is placed on one side of the front side wall of the model, a diversion ditch 17 is arranged below the front side wall, and the runoff bucket 16 is placed at one end of the diversion ditch 17 .

[0020] The device of the invention takes the pipe network down-spray rain device made of PVC pipe material as the main body, adjusts the water control valve of the rain device, and can provide the rain device with a water source with stable pressure and controllable pressure. It has been confirmed by experimental research that the water pressure in the inlet pipe of the rainfall device is linearly related to the rain intensity under the condition that the placement position of the rain device remains unchanged. The rain shower 11 and the awning 14 constitute a rain system. The rainfall device includes two parts: the main pipe 26 and the branch pipe 27, and its structure is as follows Figure 4 As shown, the diameter of the main pipe is 5 cm, and the diameter of the branch pipe is 1.6 cm. The branch pipes are parallel to each other, and the pipe wall facing the model side of the underlying surface is drilled with water spray holes 28 with a diameter of 1 mm, and all the water spray holes are evenly distributed on a horizontal plane. In this test, the raindrops were sprayed down at a certain speed, the falling height was more than 2.5m, and the maximum particle size was less than 4mm, so it can be considered that the speed of the raindrops splashing on the underlying surface basically reached the end speed. In the rainfall simulation experiment, the initial rainfall intensity is not stable. In order to avoid the influence of this part of the rainfall on soil erosion, the canvas awning 14 can be used to block the initial rainfall, and the awning can be opened after the rainfall is stable, so that the rainfall acts on the underlying surface model; The awning control rope 24 is closed to block the rainwater, and then the electric switch is turned off to avoid the influence of the residual water flow in the rainwater device on soil erosion. The sewage pipe 25 can remove impurities accumulated in the rain shower, so as to prevent the nozzle holes of the rain shower from being blocked.

[0021] The model area is composed of the model side wall 22 and the underlying surface model. The side walls of the model are made of bricks and mortar, and the cement is plastered to prevent the model from seeping water. The side partitions 21 and the rear partitions 23 of the model can be moved to make slope models of different scales.

[0022] The sampling system is divided into two parts: the sampling system for observing the total amount of sediment production and the sampling system for observing the instantaneous sediment production concentration. The former mainly includes a diversion ditch 17, a runoff barrel 16 and a flow receiving pool. After the rainfall simulation test starts, the muddy water generated by the slope erosion model is collected into the runoff bucket (if the runoff volume is too large, it can be measured in batches), and the runoff volume of the secondary rainfall can be measured through the reading of the runoff bucket; If the sediment concentration corresponding to each corresponding volume of muddy water is measured by the density bottle method, the sediment yield of the secondary rainfall can be measured.

[0023] The runoff barrel used in this device is remanufactured from ordinary plastic barrels, and its structure is as follows Figure 5 shown. Two sections of steel tape measure 29 are pasted on the inner wall of the plastic bucket, and the connecting line passes through the center of the plastic bucket, so that no matter how the runoff bucket is inclined, the average value of the water surface readings on both scales is always the water level value in the center of the runoff bucket. The water level-volume relationship of the runoff bucket has been calibrated in advance. As long as the readings on the scales on both sides are read, the volume of the water flow in the bucket has been determined.

[0024] The sampler 19 is a triangular flat funnel, which is fixed on the side wall 18 of the outflow port of the model. It can concentrate the water flow in a large range to speed up the sampling speed. The water and sand in the sampler are poured into the density bottle, and after the electronic balance is weighed, the sand concentration of the water sample can be calculated by the density bottle method.