土壤电阻率（Earth Resistivity）|接地体（Earthing Electrode）

pwm

  <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2&#46;0"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"">土壤电阻率（</span><span lang="EN-US"><font face="Times New Roman">Earth Resistivity</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"">）是表征土壤导电性能的参数，它的值等于单位立方体土壤相对两面间的电阻，常用单位是Ω·</span><span lang="EN-US"><font face="Times New Roman">m</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"">。</span></font></p><span style="FONT-SIZE: 10&#46;5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-size: 12&#46;0pt; mso-bidi-font-family: "Times New Roman"; mso-font-kerning: 1&#46;0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">&nbsp;&nbsp;&nbsp; 接地体（</span><span lang="EN-US" style="FONT-SIZE: 10&#46;5pt; FONT-FAMILY: "Times New Roman"; mso-bidi-font-size: 12&#46;0pt; mso-font-kerning: 1&#46;0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">Earthing Electrode</span><span style="FONT-SIZE: 10&#46;5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-size: 12&#46;0pt; mso-bidi-font-family: "Times New Roman"; mso-font-kerning: 1&#46;0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">）是为达到与地连接的目的，一根或一组与土壤（大地）密切接触并提供与土壤（大地）之间的电气连接导体。</span>

gubot

一般为多少?请指教