人妻 制服 出轨 中字在线

Disintegration and swelling of red sandstone under water, under the action of dry and wet cycles, after repeated action of sunlight, the atmosphere, especially rainwater, it easily disintegrates into small fragments, the volume increases slightly, and the expansion rate is about 1 ~ 4% The red sandstone after solution softens with water, and its strength decreases rapidly (some even reach about 40%).